IBS or not?

I don't really know how to start this smoothly so here it is. I'm an 18 year old university student and since this summer, I've felt quite off.

First it was an urgent need to go to the bathroom and it turned out to be diarrhea. This went on for about two weeks along with abdominal pain. I pushed it aside thinking it was just a bug. A few weeks later it happened again. Lasted the same amount of time with really bad abdominal pain as well. In between the first time it happened and the second, I had a bit of abdominal pain. This was from the beginning of August to the end of September. Before August, in July, it was only random abdominal pain here and there.

I was realizing after that that something seemed off. I began to keep a closer eye on my symptoms. I came back from a trip and decided to weigh myself. Turns out, I had lost 10 pounds in three weeks. (I weighed myself three weeks prior) Now I really wanted to keep an eye on my health. I noticed that my appetite was also not what it used to be. I wasn't hungry half the time and also nauseous. Sometimes my appetite was fine though. I also have bad fatigue and sometimes, out of no where, my throat will be sore and it'll hurt swallowing. I'm also always dehydrated.

Abdominal pain

In between all of that, my abdominal pain was slowly worsening. The locations it is at is lower right side, lower left side, higher above my belly button, around my belly button, left, right, basically at many different locations. I have an anal fissure that won't go away as well. I also realized that I'm constipated. Not the kind of constipation where I haven't pooped in a while. The kind where I go everyday but it's so hard to go and painful and it turns out it's only rabbit type poo. I have so much discomfort at my butthole that it's hard to sit still. I had anal fissures before, but they didn't give me this much trouble. I also noticed blood spots on my poo. The first time it happened, I thought it was just food and brushed it aside. But it happened a second time and it freaked me out a little. I used to only poo 4-5 times a week and that was my normal. Now it's everyday and sometimes twice a day. It climbed gradually and I'm scared it might get worse again.

I went to an appointment to see a nurse at my doctor's office. She says she thinks I have IBS, and that I should take probiotics everyday for 6 weeks until I go see her again. If it helped my symptoms, the that's what it is. But don't probiotics help sooth symptoms of other things as well that surround your abdomen? She said that yes it started this summer but university probably stressed me and made it worsen sometimes. Except it's like it's gradually worsening. I was on my study break and stress free because, hey, a study break equals a week of vacation, but on the Friday before the study week started (I had no classes) I went to the movies with some friends. I had a bit of upper abdominal pain that day but I could take it. On Saturday, it worsened. On Sunday, it worsened. In the night between Sunday and Monday, it was so bad I couldn't sleep so I decided to go to the emergency room.

IBS or something else?

When I got there and finally saw a doctor, she said it was probably my stomach. I don't know if it really was, I didn't think so, but she's a doctor so I let her continue. Well what she thought is I had heartburn or something in that sphere. The thing is is that I know what heartburn is and it did not feel like that. She gave me medication in the hospital that I had to take while they watched me to see if it worked. If it did, then that's what it was. She gave me one through the veins (I don't know what it's called) for my stomach, pills for I don't know what, and a pink liquid that numbed my throat (it was to numb the pain). She then prescribed me medication for heartburn which I never took because I know it's not that.

Now I'm at a loss. Do I have IBS or something else?

Does anyone else experience symptoms like these? Could there be something else wrong? Am I too worried?

Thank you for taking the time to read this and sorry it was so long! I have other symptoms as well but this text is already long as it is! Have a nice day and thank you for helping me if you can!