hi,
firstly, don't worry...
but you could go to the doc to arrange for a scan - you could have something like polycystic ovaries, but you would need a hormone test (blood sample) and a scan to confirm this.
Your doc will ask loads of questions such as....(were the periods you had particularly heavy - or just regular?... do you get the PMS style symptoms every month with no bleeding - or just nothing?...do you have 'problem' skin?...do you have any weigh issues?) as these are all common symptoms of PCOS.
The main drugs used to encourage ovulation are usually Clomiphene or sometimes Metformin - these will stimulate the ovaries and 'hopefully' gove you more regular periods!
Hope this information helps, but as I said at the beginning - DON'T WORRY, it'll can only make it worse!
A xXx