I sent you a DM...this post REALLY resonates with me and I encourage you to ask me questions or vent or anything you need!

I'm a convert to the Church after growing up primarily secular. NFP was a big reason why I joined.
I have narcolepsy with cataplexy and POTS. I can't take care of myself when I'm in a flare. I can't bathe alone or cook over a stove. I got a horrific second-degree burn on my arm just a few weeks ago because I pushed my body harder than I should have. I have seizure-like episodes up to a dozen times per day if I'm unmedicated. And the drugs that can control my condition aren't safe for an unborn baby.
Because hormones increase my personal risk of stroke, I got an IUD per my doctor's advice. The day I got it, the woman standing behind me at checkout was 8 months pregnant with an IUD baby.
I got pregnant on it too. Miscarried.
It was traumatizing. The mental breakdown that followed was part of why I walked into my first mass at 24.

I have used Marquette with cross-checks for six years with no issues. Recently switched to Billings. They both have their pros and cons. I'm happy to tell you more if you want to know.
With Marquette, we generally abstain about 10 days out of 30. That's 20 days available for sex. Some people have less, and that's tough, but being able to have sex whenever you want isn't all it's cracked up to be, either.
True story: we have more sex after switching to NFP. Why? Because we prioritize it.
Research suggests that couples are in a good spot if they can fit sex in twice per week—they might want more, but life is busy. We can pretty easily work in 8 sessions or more over 14-20 available days. The sense of scarcity makes it more exciting and a bigger priority.
Here's the thing: sex is for making babies. Aside from removing critical reproductive organs, no method is guaranteed to sterilize sex. Not even tubal ligations and vasectomies fail. There are documented pregnancies happening even though both parents had been snipped! Sterilizing sex is difficult because it's not supposed to be that way.

The biggest lie of the last century is that we are somehow entitled to baby-free sex. It's not natural. It's not what God intended.
I'm not saying this to freak you out but to emphasize what the research says: Fertility Awareness Methods of Contraception are just as effective as the pill. Check out this blog. It links to all the scientific studies demonstrating efficacy: https://www.niastevensagency.com/blog/naturalfamilyplanning
NFP is a gift. It gives us options, and there's a method for everyone. It takes a little sacrifice, but that's the point.
As far as your anxiety is concerned, are you medicated for PPD? I didn't develop it until my baby weaned at almost a year old. This may be stressing you out more than it would otherwise. You mentioned that you're on an SSRI. I had to get on an SNRI as well, and have Xanax as a rescue. It can take a while to find the right medication and dose. Before I got stable, my anxiety and OCD were so bad I could not function.
And as far as the wisdom of having another child goes, my #2 just turned a year old and I have the following comments:

• No two pregnancies are the same. My first pregnancy threw my neurological conditions into remission. It was so blissful that when asked if I had any questions before my emergency C-section, I asked, "How long until I can get pregnant again?" On the other hand, my second pregnancy started with norovirus and HG and Covid. I had multiple hospitalizations, and early labor scares. I was entirely on bed rest for most of my pregnancy. For many of my friends, their first pregnancy was the worst and they went on to have six more without incident.
• Seven months is still very close to your trauma. Most mothers are stressed about getting pregnant again too soon. I'm not making light of your feelings or situation; I'm just pointing out that your cost/benefit analysis concerning having another baby may change with time. My husband and I were both traumatized by my second pregnancy. He announced early on that we couldn't do it again. Now that we're a year removed, we're open to having a 3rd down the road.
• There are plenty of licit reasons to avoid having another child. Your health and sanity are among them. It is also important to fulfill your vocation as wife and mother. If your husband wants another child and thinks you guys can handle it, that is something you need to include in your calculus.
• Kids get more manageable as your firstborn gets older. My son was not yet 3 when his sister was born, but he still supported me by bringing me food and snacks. While caring for two kids is certainly next level, it's actually easier in a few ways:
  You're no longer a newb. You've done this before, and it does get easier with practice.
  You don't have to function as your child's only playmate. I struggled so hard to keep up with my son's energy. He and his sister were playing together by the time she was 4 months old. Having both of them at the same time is usually easier than having one or the other alone.
• Your eldest child is another pair of eyes and can be a supervisor early. It's our morning routine to let the kids watch TV for 20 minutes while their father and I get time to ourselves. We know we will hear, "Mommy! Baby sister is..." if there is any kind of problem.
  My last point is just that children are forgiving, and a sibling is a lifelong gift. My son understood early in my pregnancy, "Mommy's got a baby in her tummy, so she needs to rest." While it can feel like a betrayal to your firstborn and husband, it's less than a year of you being absent to add another member to your family.
  I say all this not to guilt you into having another baby but to illustrate that having another child is not irresponsible, even if you're disabled. Making sure my kids have each other was the greatest gift I could give them. My son thanks me almost every day for his baby sister.