Hi , Im 14 Years Old And In The Last 5 Months I Haven't Gotten My Period . Yes I Know What You're Thinking Maybe You're Pregnant But Nope Im Not Sexually Active Trust Me , Anyway I Had A Doctor`s Appointment And The Doctor Prescribed Some Pills That Were Supossed To Start It Back Up And It Did For About 3 Days Ever Since Then I Haven't Had It . Is There Some Time Of Hormonal Imbalance Going On Inside My Body ? And Why Do I Have To Keep Starting It Manually ? Please Write Back ASAP .

P.S - When I Was About 10 I Was Put On Birth Control For MY Abnormally Long Cycles Which Lasted About 3 Weeks . Could That Have Something To Do With It ? Will I Ever Get It Again ?

I'd suggest an endocrinologist. It could be thyroid or any number of reasons.

Are you still on birth control ? If it was controlling your period, if not on it, why did you stop

I Stopped Taking It Because Some Days I Would Forget And Instead Of Messing Up My Body Anymore With The Pills I Just Decided To Stop Taking Them All Together .

We can't possibly know which of many reasons your periods are unusual apply to you.
You need to discuss all of this with a parent and your doctor.
Deciding to stop taking the birth control based on the idea that they were 'messing up your body' indicates a lack of maturity and knowledge of the situation. I don't know if the doctor never explained it all to you or if you just chose not to listen. Go back and ASK.