Annoying MIL

So last night I came home from a 12 hour shift, I was exhausted and on top of that I had a migraine with dizziness. I just wanted to go home and get ready for bed and be in bed by 8. My 5 month old was being babysat by her for a few hours since my husband was busy doing something. He is usually the stay at home Dad. We get our son back and he is obviously over tired. Can't settle down. Just whiney and cranky. I start our nighttime routine and it's not working. I lay in bed with him maybe that would help him fall asleep, and nope...hes wide awake. Even my breast is not helping. He's nursing and whining at the same time at this point. I am annoyed because I start to think well maybe my MIL didn't let him nap. I pick him up and hold him and walk around with him patting his butt (exactly what she does when we go over) and it puts him to sleep within 5 minutes. He never gives me any hassle going down for bedtime until now. I really feel like it was something she did or didn't do today while watching him. What do you ladies think?