Worried about multiple cancers!

So I'm 30 years old and I'll start out by saying I have terrible health anxiety. I'm on medication and I've been feeling absolutely great except for the last month. On February 7th I was a little constipated so I took one dose of Miralax. Then the next day, terrible diarrhea! Going 10+ times a day. It has not stopped since. Mornings are the worst. I go at least 3 times before work. Probably one time at work. Then 3 times or so after. I can even see chunks of what looks like undigested food. I definitely see mucus in the toilet. I havent seen any blood. I can hear my stomach gurgling a lot of the time. Pressed on my lower right stomach below my belly button this morning and felt a squishy sound like water came out (hard to describe.) I've had back pain on and off for months but I do work at a preschool and sit in the tiny chairs and the floor all day, but I feel like the last 3 days it's been constant. Thursday was the worst, but it's not as bad now. Feels like I constantly need to stretch.

Anyways, my doctor tested for celiac, got a CBC, CMP, and a stool test. Everything came back fine. No infections, no parasites, no viruses. Blood test were in normal range. The only thing that was detected was the cdiff gene, but not positive for an active toxic. Also negative FIT test. I've tried Imodium, Pepto and one other thing to try and help and nothing helped! My doctor put me on cholestyramine and it made me super bloated and my stools did harden a bit but they were flat or small pieces. So she had me stop it. I am seeing a gi specialist she referred me to on April 9th but I feel like I can't wait that long! I'm terrified I have colon, gallbladder or pancreatic cancer!! I've had these symptoms for a month now and they aren't letting up. I did just start Zoloft on January 3rd and my doctor mentioned that could be causing my problems but I just can't imagine that would cause this!