Help! They don’t know…

Hi, i’m 20 & recently been diagnosed with autism & ADHD after a very long uphill battle. None of my boyfriends family know this and it makes social situations SO difficult! My boyfriend seems to think i’m OK when socialising, but i hate it so much & I dread every birthday / special occasion etc

I’ve been asked to go for a meal & drinks with his family but I really don’t want to go. I just feel like it looks so bad If I make up some excuse but I get myself in such a mess - I feel physically sick & get upset stomach every time i’m very anxious & it’s just effecting me mentally. Sounds so silly but I’m really struggling - am I a bad person if I don’t go? i just feel so guilty for not being there for my boyfriend…