Need some advice

So according to the app I am 11 weeks today.

This is my third pregnancy and we couldn't be happier. But yesterday I started to experience some really intense lower back pain with some pretty narly cramps that would come and go all day yesterday. My husband bought me some Tylenol and it helped me sleep but I woke up with the runs....gross I know but I didn't experience these issues with my first 2 pregnancys. Woke up this morning feeling a bit better still a bit runny but I'm starving I'm not sure what to eat to help settle my stomach to where I don't throw up...any suggestions?