Mystery stomach problem .... HELP!!

Hi everyone I'm 22 years old, and ive been having this weird stomach problem for a month now!! Here were my symptoms: a lot of straining when pooping, needed green tea to help the poop come out, gassy stomach with pains that came and went, the feeling that i need to poop but nothing comes out. But my symptoms changed to this: I can't poop without a stimulant laxative, mucus in my poop, no pains, i still pas gas normally, i still have my appetite, sometimes i get stomach noises i don't know if its normal or too much. It's confusing because i feel 100% fine, i don't feel ill or anything. I'm calling a GI tomorrow to see if i can get in as early as possible, is anyone else experiencing this??? or does anyone have an idea of why this is happening??? I'm scared it might be something serious like cancer and that i'll need a colonoscopy bag!! i'm trying to stay calm but it's hard!!