pains in abdomen after eating

So lately I’ve had some problems after eating

After I eat a lot or have really strong foods, I always get major pains in my lower abdomen and/or sides of my hips. It hurts to do much and I just lie in my bed in pain. because of this I try to not eat as long as I can which I know isn’t healthy, but it’s better than dealing with the pain. can someone explain to me what’s wrong? is it because I may not be eating healthy or too much at once or not digesting properly or possibly gaining a lot of weight?