Hey, I'm so sorry you're feeling like this. Early pregnancy is such an anxious time and I'm sure the fact you've been through a lot to get there I'm sure won't be making you feel any more relaxed.
It's very hard to just make yourself relax. Talking your fears through with someone may help - I was referred to the perinatal mental health team in my first trimester and having someone external to talk to made me feel much better.
I tried distracting myself with anything else I could. It can also help to give yourself a designated time when you're 'allowed' to worry, say half an hour a day. The rest of the time when you find yourself having anxious thoughts, acknowledge them and then try and move back to what you were doing before. Mindfulness basically. There are apps that can be useful for training your brain in this way, like Headspace.
Your hormones are also going crazy early in pregnancy and they often stabilise once you get into the second trimester. I really feel a lot of my anxiety and weepiness was hormone induced! You have to hold on for a while and ride it out, doing what you can to make yourself better in the meantime.
Symptoms come and go in early pregnancy so they're not a very reliable indicator of how things are actually going. Try not to fixate and try not to google too much. The problem is there is no certainty - and there still isn't actually, I'm 32 weeks now and still have some anxieties around things like stillbirth and potential abnormalities. You do get a bit more used to the uncertainty as things go on and more accepting of it.
You will be OK, but don't feel alone, you're far from the only one feeling this way.