It sounds like you are having a tough time but I'm glad that you decided to reach out to us. Pregnancy can affect your hormonal levels as well as mood, which can be a reason why you might feel more anxious. I'm not sure if you've seen someone in regards to your anxiety or spoken to someone about it. If not I would suggest reaching out to your GP and asking whether you could see a psychologist or counsellor to talk about your current situation. A psychologist can help you with your symptoms of anxiety and can also identify what triggers it and provide you with ways to help manage it so it doesn't affect your life.
It is normal to be anxious at a new job, so try not to be too hard on yourself. It takes time to get used to a new environment and a new job. In terms of your boss, he might have been upset at the time, but it doesn't mean he will hold it against you. All you need to do is to try your best, do the work to the best of your ability, your boss will see that and he will appreciate your hard work and efforts and he will be happy.
I know with the pandemic life seems to be a bit more negative, but know that things are constantly changing and we can only hope for the better. Hope this helps.