What may be causing my diarrhea? (PLEASE answer)?

okay, so I live in Tennessee. for my summer vacation, i decided to go with my dad in his 18 wheeler to Sparks , Nevada (where I am now) , which is about 2500 miles from my house. I do have an irrational fear of public restrooms, so I haven't gone since Wednesday until this morning, when I went a little, but it wasn't diarrhea. Then just now, I went because I had some stomach pain below my belly button, and it wasn't quite liquid, but it wasnt hard like this morning. Im a total hypochondriac, so Im freaking out. Could I be having diarrhea from not going for too long...? please answer, and thank you so much!