I Haven't Been Eating Normally And When I Eat, I

I haven't been eating normally and when I eat, I don't feel like eating. Im perfectly fine with my body, but lately I've been noticing that i start getting random like this feeling like a fever and I feel weak. I get this stomach pain and I start gasing a lot lately. The fever pain goes and comes away. I don't know what's going on with me. Even after I eat this still happens.