Doctors won't let me take my kids

I need some recommendations! I'm running out of options. Last month I had an ultrasound for complications I was having during my pregnancy I have two boys who both are autistic and my husband signed his rights over last year. I made the mistake to have a one night stand a few months ago and ended up pregnant I have no family or friends to help watch my kids I legit call someone everytime I have an appt and they say no or there bust my mom passed so she's not here to help:( but last month I took my boys to the ultrasound visit as long as my oldest was wearing a mask. Today they stopped me and told me turn around and go. I said why they told me find someone to watch those kids or no appointment for you. I told them that I have no sitter ever everyone works and everyone is to busy and they told me they didn't care to call my doctor. So as I'm walking to my car completely bawling because I wish these hospitals would be a bit more understanding parks are opening shopping centers are open and kids are there and I can't bring my kids to a doctor's visit. I haven't had one real ultrasound because the first one the baby was still to early to see. My doctor told me the same thing and said just go find a midwife then and hung up in my face. Its difficult and I had so much bleeding with the pregnancy and so many complications and I can't even be seen for anything it really sucks and hurts me.