I am 17 years old and I have had a pain in my upper left abdomen close to my left hip for around a month I started getting worried after over 1 week of it happening and then around 2 weeks of the pain happening I went to the bathroom to poop and as I was pooping I was straining harder than I ever had before and I saw blood on the end of my stools not mixed in it was a more than little amount I flushed it and I probably saw a piece of bright red blood on my toilet paper but it was small. I told my mom to bring me to the doctor but she said that it was probably low fiber so I ended up switching my diet on the same day my mom made me salad and toasted wheat bread and the next morning my stool came out completely normal no blood in sight and there has not been blood ever since but the aches were still there so I went to a doctor about the aches and she said that it IBS but sometimes its hard to believe in the span of the past 3-4 weeks I lost weight that I link to Cancer but I think it might be due to me barely eating enough I went to eating big meals from breakfast to dinner often over eating to eating stuff like toasted bread or boiled eggs for breakfast and small amounts of oatmeal for lunch and for night time i generally eat an average amount of cereal also ran a couple miles 2 times in this span, I probably have ate well under 1000 calories some days. The amount of weight I was 4-5 pound from my last check up which was three weeks ago when my symptoms started. And I have been obessed checking my poop even though there is nothing. Also the aches have gotten better they leave body like an hour before I go to bed and for my weight I tried eating more to see if I can add on weight. My parents and doctor have noticed im anxious and said I do not eat anything. I also never pass gas or burp and I have an on and off pain in my lower left rib. Can symptoms just leave such as the blood incident it only happened one time it might of been a hemmoroid but I feel no pain but I remember month ago I wiped hard an saw fresh blood so I dont know plus my stomach and abdominal pains get better when I tend to relax but irritated after some foods but they are not as bad as they use to be.

I have no history of colon or bowel cancer or anything related to it M y mom thinks im inflicting pain on myself due to putting pressure on my abs see even said she went crazy that she might have breast cancer due to pain but was all clear for test and then the pain went away. When I go to sleep the pain goes away .
I am also obsessed with measuring my weight as im scared of that but due to flucutation i never know I checked my weight all day with different varying results
For what stem my stomach problems was from my checkup when they found microscopic urine in my pee but said it was probably an infection and sent it to a lab but never got a call back its been a month but my mom told me that it often happens to her and to stay calm as my doctor was calm to but I started searching stuff up on google and I though hard on it and the pain came right after I was feeling well I know that caused me to be like that

But for now Im still scared but the stomach pain are almost gone and I know my weight probabl has to do with my anxiety lack of eating