Irregular Bowel Movements For 3 Years!?

ok so back in 2007 when i was in 7th grade i started to started to take a new medication for my ADD. soon after i started to notice it was kinda hard to p stools. i umed it was my medication. so i ate oatmeal for breakfast for 1 year straight. which helped alot. after 2 years that medication was taken out. which was like in 2008. recently i have just began having my periods. (july 09) it has been like a week after my period and my stools are almost like pebbles. its hard to p even though they are smallish. but i managed to successfuly. i havent taken a stool for about a week which is weird but now i can sorta go. ive been eating fiber one bars and fiber 1 poptarts and fiber pills. they hardly work. its been about 2 days. so today i had roughly about 15 GRAMS of fiber. and its barely helping. what should i do? my mom thinks im fine but im scared! :(