It’s taken me years to realise that I might be slightly autistic. A diagnosis won’t always be useful but looking into the traits of the condition might help you in determining if you are too. In terms of dealing with you anxiety, needing space, dealing with in-laws, etc. Try CBT- cognitive behaviour therapy. Ask your dr about it if you’re in the UK.
Apart from that, be open and honest with your husband- try explaining that this is not you choosing to be like this but something you FEEL. Most of all, cut yourself some slack- we’re not all designed to be the hostess with the mostess or social butterflies.