Hi, I Have Been Having Stomach Problems For Awhile. When

Hi, I have been having stomach problems for awhile. When I eat, it seems like I have trouble with my total digestion. I try to go to the bathroom and it feels like I am blocked. I have pain so bad it feels like I am in full blown labor. I feel like I am about to pass out due to the pain. Then when I finally do go to the bathroom, it is intense. Afterwards, I feel much better, but weak. I am becoming more and more afraid of eating because I know I am going to be in so much pain. Can you tell me what may be causing this? This is becoming more frequent .