super late, but virgin

so i normally have a cycle that's over a month. about 35 days? it's fairly regular. but it's been over a month since i was supposed to get it (jan 22). i'm 16 and a virgin, but i've had TWO dreams of pregnancy. i am normally regular and have terrible pms but i havent had any (then again, i'm taking zoloft now to balance my mood. but i started that three months ago and ive had a normal period since). could it be that i've started excersizing after a long period of being sedentary? please help!