Why haven't i been hungry lately?

im not sure why but i haven't really been hungry lately. when i do eat my stomach starts to hurt. i also have diarrhea, my poop is yellowish and really watery. i hear things in my stomach, i'm really gy. i have been farting a lot, and feeling really bloated. but im also coming off the flu right now so maybe that has something to do with it. my stomach hurts sometimes just randomly as well. i cant really sleep right now its like 4 in the morning and i should be. could this be a parasite? or is it just my body readjusting. its really scaring me. i've already lost 5 pounds in the past week. what should i do? and what could this be?