Side affects

I am in the middle of my 3rd month of Loestrin 24Fe I should be getting my period next week. But I got cramps last sunday and I got a full blown period this week. I still have been taking my pill every morning. I has been spotting on and off since I started taking the pill. My question is, is this normal to have break through bleeding in the middle of pill cycle? When does the spotting ever stop and should I keep taking the pill. Thanks :)