period came early... I think!

Val
So this is my 3rd month on clomid. This time was 100mg. My periods are normally right on time. This morn I woke up with some minor cramps and this afternoon I went to the restroom and am bleeding. Not a ton but dark red (which is how my periods normally start). Could this be IB or could the clomid just made me early. This month is my last chance and I'm already devestated thinking the worse!