How to keep up Brahmacharya

I am 17 year old and had been doing brahmacharya for past 12 days but had a break just two days ago. Now i cannot start it again as sexual energies become quite high and my will is also weaken.so wat do you suggest? I do yoga but what else do i do to give it a kick start, as when i continue it for 1 week or so then my will becomes stronger and i can stretch it for longer periods.