Irrational anxiety

I recently posted this on the chat thread and was recommended to post it on here. Hope this is okay?

So I’ve suffered with relationship anxiety all my life (not had the best relationships in the past and been through some trauma). I’ve been with my partner now for 3 years and we’ve just found out I’m pregnant. It wasn’t planned but we had said if it happens, it happens. When we did the clear blue week test, it said I was 2-3 weeks pregnant and when we thought back to 2-3 weeks prior, we had sex only twice in that time frame and we’d also been out with friends and drinking. Now, I often will think of “worst case scenarios” and I know I have “irrational thoughts” and all of a sudden (on the day I found out I was pregnant), I thought, “what if I was that drunk when we were out and I slept with someone and I can’t remember it. And what if the baby is not my partners?” I can totally see how this is irrational. I’ve never done anything like that before. I always used to worry the day after being out and drinking that I’d kissed someone but after speaking to my friends, they always told me I hadn’t and not to worry. I guess now my worry has escalated as I’ve found out I’m pregnant so instead of thinking I might’ve kissed someone, I’m thinking I might’ve slept with someone.

Anyway, thinking back to the conception, I keep thinking back to the night outs we had, we had around that time and we had a fall-out both nights we were out and my thoughts are “what if I got so angry at him I slept with someone else?” But I can remember both nights we were out and, although there are some gaps in my memory (as there usually is when you’re drunk), I’m sure I’d remember sleeping with someone else. I feel so crippled and it’s affecting EVERYTHING I do. I’ve spoke to my partner about it and he says I’m being silly but I can’t seem to shake it off. I don’t know what I want to gain from posting this on here but I just wanted to try and see if it helps anyway. 

I’m 32 years old, this is my first pregnancy, I love my partner but we do have arguments every now and then as we’re both very fiery. I’m on anti depressants anyway for anxiety and I’ve been to therapy in the past for worrying I’ve done something on a night out that I can’t remember. Please can someone help?