How do you deal with anxiety around your partner?

I hadnt been on this reddit in a couple of weeks because I genuinely was having a lovely time. Attracted, happy, enjoyed being around my bf. I do not understand what has happened but this past week I havent felt as connected to him and after spending time with him yesterday, I woke up so anxious today and feeling like I need to end it. It's like a sudden switch has flicked on where Im doubting everything, dont feel attracted, constant worrying and i feel like its a bad sign only 2 months into a relationship? I felt so guilty i didn't spend the night with him like i was supposed to.

How do you deal with going on dates and spending time with your partner when your mind is constantly telling you to leave and end it and that you dont even like them?

How on earth do we deal with this and how can I go from being really happy to stressed overnight?