I've also been struggling to loose weight.
I don't know much about it but I would schedule an appointment with the doctor
It could be PCOS or maybe a thyroid condition that's causing the irregular cycles. I'd recommend your OBGYN or a fertility specialist (reproductive endocrinologist) due a full workup that includes tests for abnormal levels of LH, testosterone, and thyroid hormones. Weight is another factor, as you mentioned. Most likely you'll need to take a prescription to bring hormone levels back into a good fertility range - the prescription would be temporary, of course, during your preconception phase and partly into your pregnancy when it happens. Good luck!!
go to the doc and get a blood test or they may send you for an ultrasound, they thought i was pregnant at 16 coz i stopped getting my periods and was putting on weight... but it turned out to be pcos. if it is pcos dont despair because they have great medications they can put you on to help you conceive. i have pcos and i am on metformin, it has regulated my periods and im ovulating again! there is hope if it is pcos :)
you need to see your gyn. im also ttc for over a year n few months now, you are just 19 still have lots of time. as for weight loss, well, im not sure if its for everybody or not, when i was ttc i been told to go to see a fertility dr. but for us its expensive, so i was like let me see if i can get OTC fertility pills if it works its gr8, so i tried fertility blend for women on november 2011 i used for a month, it says u need to use atleast 3 months.
sadly, it gives me diareah( loose BM) and weight loos, so i had to stop that, i lost 5-7 lb in one month. however i need to gain my wt (NOT LOSE) just ask your dr, if you can try this or not. u can get them at GNC $40. it says it aslo mange ur cycle days too.
oh sorry u r in UK so i dont know the price ther .. u can reserch on this product. and ask ur gyn b4 trying, i did b4 i used dr said its ok u can try if anything abnormal discontinue, so i did. but it did made me to loose my weight.