Think i might of started my period, or haven't i?

last month, i had dark brown discharge, with a shiny, maroon red, blob in the middle, and din't have anything, until a few days ago, again, it lasted for 2 days ish, one day, just light brown/yellow discharge, the next the same, but a miniscule pink, dot in the middle.... have i started my period, i did have stomache pains last week, i could prevent them, by clutching my lower belly, or running, standing would really hurt, have i started? or will i start soon, if so- may you roughly predict when?