Uterine contractions

I'm 6 weeks along, and I was eating fresh cherries and prunes and drinking a pot of honey lemon while chatting with friends. About an hour in I suddenly felt my uterus squeeze and twist. I stopped eating and drinking immediately and stood up and walked around, but it didn't stop for a few minutes, after which I had a lot of white discharge. May I know if this is normal, or if this may be something triggered by what I was consuming? I didnt bleed, thankfully, going for my first ultrasound tomorrow and will check that everything's fine.