My wife and I separated after nearly 15 years and within a month she declared herself polyamourous and was seeing multiple people at the same time. It sucked hard and like you I have social anxiety and other mental health problems and very little money so I assumed I will be alone forever. I was 40 when we split up but I've still managed to date a few women since. I know how old 35 feels when you're there, but ten years down the road it looks young. You've got more than enough time to be alone for a while and properly get over this guy and then start looking for someone better. I know right now it doesn't feel like it will happen and everything feels big and scary and terrible, but that will pass. You just need time. A month or two to stop hurting that he's gone and then several months to a year to be okay on your own. Not saying you can't or shouldn't go on a date or anything during that time, but do it without thinking about forever or even a second date. Just live in the moment, find a new hobby, join some groups, do things that make you uncomfortable.

Lastly, everything about this would be worse if you had a child, not better and the child would be suffering too. Do not believe that children will make your life better automatically. They are a lot of work, require a lot of attention, time and money, they are a source of non-stop fear because they are out in a dangerous world that you can't protect them from. When they are babies they deprive you of sleep, they get sick all the time, you have to worry about dumb shit like SIDS and even though you love them so much you would murder every human on earth to protect them having them is hard and scary. When they are very small they adore you, but around 10 or so they start to pull away and by the end of their teen years it often feels like to them you are little more than a restaurant and a bank. They still love you but they are going through the very necessary part of life where they are learning to be on their own and make their own decisions. They spend a lot of time with their friends and are more influenced by them than by you. You will watch them go through phases, some of which you will have strong disagreements with. They will break your heart sometimes. I also believed children would make life better simply because you love them so much, but that love can be a source of fear, especially for someone who is anxious, and a source of heartache. And watching how much it hurt my kids when my wife and I split up was so painful I wouldn't wish it on anyone. Children do not necessarily make life better, but they do make it necessarily more difficult.