New to this site - Think it could be IBS

Hello all Right, im new to this site and i just wanted to explain my problem to you. I have always seemed to have bowel problems but for the past year or so they have got worse. Im currently on lactulose to help me go. I go to the loo everyday and i think everything is fine until i have like a build up. Im very slim (size 6, 7stone) so i can feel everything that goes on in my bowel (eg. if i push my bowel and its blocked there will be a lump). Im also 17 if thats any help. I cant eat lettuce, pasta, noodles, orange juice, anything hot (eg. peppercorns or chilli!! it will make me go too much and have horrid pains.). Im a nervous person, so that probablly doesn't help. Im on tablets for that though. If i dont go to the loo for a day, then i will get really really bad pains etc. I am just wondering if this sounds like IBS? Thanks guys!