Please help, i havent had a period in a year?

its been a year now since i came off the contraceptive pill. i went last nov to see the gp and told them that i hadnt had one. theyt said it wes just my body getting back into a routine! and a week later i had slight spotting so i assumed i was back to normal... then since then i still havent had a period. I went to the doctors in march and they took blood tests but they found nothing. im terrified iw ont be able to have children but the doctors just dont seem to understand whats going on. im 18 and was on the pill for about 2 years... could i be infertile? im scared