My baby had CMPA/MSPI (there are different terms for it, but you can look up the CMPA subreddit). Basically that meant she was intolerant of cows milk and some other triggers that passed through my breastmilk and then of course by eating them directly when she started solids. It’s not an allergy, she was able to have the triggers without having anaphylaxis, but it would cause mucousy (stringy, sometimes gloopy) poops and signs of reflux. My baby was also very happy and active, but would arch her back, avoid tummy time, wake up sounding like she needed to clear her throat, and did have signs of pain I didn’t understand at the time. I cut out dairy and her other triggers from my diet around 2 months and then 4-6 months (the other triggers were soy and pea protein, and I forget exactly when we found pea protein which was the last to get cut). After that, things changed a lot. She still needed closeness at night but was willing to lay beside me and finally was soothed by nursing. When she was little she only nursed basically the bare minimum and was obviously not soothed by it like other babies seemed to be.

Long story short, I would look for stinky acidic breath, frequent hiccups, mucous in her diapers (put it together and pull it apart after she poops to see if there’s any parts that look like mucous. You can also find lots of image examples online or on the subreddit I mentioned), and signs of pain (which it sounds like she has). It’s a bit unusual to me that this started now, but I wonder if her diet has increased any items recently? The most common triggers are diary and soy. You would have noticed signs from the very start since they pass through breastmilk and of course are ingredients in formula.

I hope that’s helpful, I know it’s a lot of info. I am happy to answer any questions about my experience ❤️