What’s it like being raised as an ONLY ?

We have a son (1 year) and we have made the decision not to do IVF again. It took over 6 years to have him. After many losses before my son was born I don’t think I have it in me to continue. I tried and the thought of it makes me physically ill. We’re older parents (not by choice) 34( F) and 40( M). I’m worried about my son being raised as an only. I’m worried about loneliness and him being alone when we’re gone, I’m worried about loosing him, worried about him lacking social skills , worried about us being a burden on him when we get older and the list goes on…… We really try to do our best as parents. I have childhood trauma due to violence and very little memory of my childhood. I’m not an only but I don’t speak to my brother. In addition to that I have trauma from multiple miscarriages, infertility and birth trauma. My husband also grew up in around domestic violence with 5 siblings which he very rarely sees. I’m in therapy and working on myself to become the best parent I can be. I worry that my child will hate me one day for not giving him a sibling… What was it like being raised an an ONLY?