MIL can be lovely and can sometimes be moody and bad-tempered without actually saying anything. She was over last week and dh and I were tiptoeing around her she was not being her usual self - uncommunicative, not interested in anything I had to say, very very down. I asked dh if we should ask her what's wrong - he avoids confrontation and believes that if something was wrong she should have said so herself.
I tend to speak to her daily and called a couple of times - sounded really grumpy - but she has not called at all so after a while I stopped as well.
Anyway, this week was our anniversary and she came over with presents and a card and was completely normal. I was surprised as she was completely different and made no mention of her earlier bad mood. AIBU and angry that firstly she comes over and inflicts her bad mood on the whole house and then when she's more cheerful expects me to forget everything without an explanation. She does not have mental health issues and is not bi-polar.