Am i normal?

hi my name is shaquetta and im 18 in dec 23, 2007 i started my period and got off in march 2008 i was only off my period in march for about 2 weeks and started back up agian its now been 5 months (Sept. 4 2008) and i still havent got off it ussually goes away after 2 or three months and ill be off for about the same amount but this time its lasting forever and im not showing any sign of clearing up last year my doctor put me on birth control which kinda help it clear up but it caused me to gain a large amount of wait, get really bad cramps and i always felt really nausus and really tired they took blood samples and i had a pap smear but everything was normal and on my period i dont get any cramps i really hate it because i dont like to have sex on my period with my borfreind and its impossible to get pregnant i have been trying 2 get pregnant since 2006 and it hasent happened yet can any one help me?