yes you can have any time between your last period and next some women have it with the start of their next periods it just depends on the woman
can you still have old blood even if your period ended 2 weeks ago? for me it ended on the 4th of july .... im used to having spotting before and after my period...before is a little weird but i get if from time to time and after my period its super normal..but its only happens 1-2 days after my period has ended
i don't think this bleeding has anything to do with your IBS and i don't think its implantation bleeding(which is a sign of pregnancy) it sounds like its just old blood some times when you have your period not all the uterine lining gets out sometimes you'll have a little brown spotting or wipe and there will be some dark blood but its just left over from your period it's not something you need to worry about unless it starts to happen alot and then it might mean something but for now i don't think you have anything to worry about
i really wouldnt wurry to much i was on the pill for 5 yrs then stoped it one of my early period signs was brown discharge a bout 2 week before it could just be your body changing if your still wurried about it when u have a doc appointment just bring up the subject and they will check u out