Stress, alternating D and C

edit: I have never been diagnosed of IBS yet, my doctor suggested it, but without doing extensive testing, which somewhat angers me because he seems to just write me off without properly testing.

Hi everyone, I am a 21 year old male currently attending college. For the past three weeks, my life has been plagued by stomach issues. I have been extremely stressed over midterms / assignments / projects. My stomach has always been an issue for me, ever since I was very young. For the past three weeks, I've had anywhere from abdominal pain followed by D, then normal BMs, then a random bout of watery D, back to normal BMs, then constipation which also led to some bleeding (which really freaked me out). Skip to today, I am back to D. I still have several midterms this upcoming week, and am starting to feel anxiety crawl up my spine. I wake up every morning and the first thing I think of is "Is my stomach feeling okay? Do I feel like I need to go, will I have D or will there be blood in the toilet?" I have been to my college clinic, and was seen by a doctor that didn't seem very invested in my problems. I can't blame him, who would want to deal with this kind of issue? We took a stool test for parasites / bacterial which came back negative. I am now waiting for blood results for Celiacs and also an Xray of my abdomen area.

I am at my witts end. I have never had it this bad when it came to stomach issues. I've always been prone to getting stomach pains and then d. I have had some bleeding about 3 times in my life. Had a stool sample for colon cancer about a year ago that came back negative. So what can I do? If the celiac / xray come back with no results, what should my next step be?