Morning sickness?

I've been clear from morning sickness since 12 or so weeks! Even before then it was mostly just a lot of nausea. Always hit me around 10 or 11:30pm
I'm now 33 weeks and the last 3 nights I've noticed I'm super nauseous again around 11. 
I don't think it's a stomach bug **knock on wood** because I feel okay during the day!
Is this a normal thing to happen?