TMI. Not sure what going on with me

Not sure how to explain this and sorry if it's to much info. Everytime I eat like dinner lunch or breakfast 30 mins later I have to run to the bathroom and literally run because of diarrhea. And it's not normal it's literally just liquid coming out of me. It's been going on for two weeks straight now. At first I thought it would be because of a flu but I feel perfectly fine other then having to go to the bathroom. If I don't eat at all it doesn't happen and if I have a snack I'm still perfectly fine. But when it's dinner time or lunch or just a meal in that case. Afterwards I have to go to the bathroom and hurry. I want opinions before I go to the doctor to get checked out. Also is this going to make me lose weight?