Feel like I urgently need to s*** all day but I can't??

I don't think I've ever really had this happen to me unless I'm on my period (and I'm not right now, it says my next one is in 6 days). But I have discomfort in my lower stomach which basically feels like diarrhea cramps. I went to the mall today and had to go to the bathroom like 5 times because I thought I urgently had to but nothing was there. I still feel like that now. I literally sat on the toilet for 45 min and nothing. I don't think I'm constipated or anything. I eat a lot of fiber but have steadily been eating that much for a month now. Should I be worried?? Wtf is this😥