it's very difficult if not impossible to defirentiate the 2 i'd say. lol (not much help i know) the main one i found was the breast tenderness with my 1st pregnancy i never get it with my period and the peeing alot!!!
my second pregnancy i'd of swore blind i wasn't pregnant and if it wasn't for...
could be all the stressing that surrounds trying even tho u try not to think abt it you do, so could b that knocking your cycle off, but i'd def c ur doc they can take blood to test for you.