Don't want to attend family gathering

[Ellarain]

So our nephew is getting christened tomorrow and I don't want to go. Nephew is the son of my DH brother. Family relations have been difficult at times and I really don't have the energy. I can never win with them, if I talk they find a way to twist what I have said, if I'm quiet I'm being rude. I haven't heard from SIL who's child is getting christened since March when they got married. I realised that I was always the one reaching out so stopped and I haven't heard from her since. She text my DH about the christening. I'm not on speaking terms with my mil either. I just feel like I'm tolerated my his family and I get terrible anxiety before, during and after any family gatherings. DH obviously wants me to go with him but I really don't want to. If I don't go I don't know what DH should say to explain my absence.We have another christening the same day which I will be attending with DH. BIL and Sil know about the other christening. What should I do?

Thanks for all the advice. DH asked FIL about the church service. Due to Covid numbers are limited so we can't attend the service. I would have attended the service and got it out of the way. I can't attend friends on my own due to the logistics of travel and only having one car. Mil has always had trouble respecting boundaries and has been very horrible towards me for years. DH has only noticed it over the last four years and has challenged her about her behaviour. She didn't like this so relationship between DH and mil not good at the moment. DH is a people pleaser and just wants everyone to get on. He thinks that if I don't go it will make everything worse.