loestrin i had spotting and this month i have really light bleeding. is there a possibility i might be pregnant? on loestrin i never know when i am going to get my period while with the other i always knew when i was going to get it. is this normal? also i recently got put on antiboitics while i am on the placebo pills and i am supposed to start a new pack tomorrow but i am unsure if my irregular periods are a cause for concern.