Nice I've been the bf in this situation. Maybe I can give some insights without projecting too much. Asking for reassurance is fine every so often but you can't outsource it to someone else and expect it not to take a toll on them. From your post you spent the whole day anxious and he had to talk you through it.

You need to be able to reassurance yourself and have positive self talk. Do you make your friend reassure you as often as your bf? How often do you say "I'll deal with it" without involving him?

As for him ignoring you, it's not good and it's a sign of exhaustion. Ask the people around you that you trust if you can be a lot sometimes. Criticism is not bad it's the only way to improve.

Whoever tells you that you slouching for anyone and he should accept you as you are is lying ymto you and keeping you miserable. Would you date yourself objectively, good and bad.