What could this be?

Brooke
For the past week and a half or so everytime I eat something it messes up my stomach and makes me feel really bad and I usually end up going to the bathroom 3-4 times and it's loose. I haven't done anything different I'm always drinking something and even stuff I use to eat all the time before this does it. What could be making this happen? I am 34 weeks and 3 days