Nausea every night!

Jessica • My name is Jessica. I like to watch Inyuasha, hang out with my kid, and work on my book. I'm 22 years old. :)
I don't know what's going on! I've been feeling nauseous every night! Anyone know what might be the cause?
If it help I had my baby dec. 5th. And I am not on any medications. And I breastfeed.