I plan on skipping my period next month with the use of birth control. how likely is it that i will spot or have breakthrough bleeding?

Pretty likely: If that is the first month that you have tried it. It sometimes takes an average of 3 months doing straight through birth control for your body to get used to it. If you continue to have breakthrough bleeding, you might need to try another pill. Try to take pills very close to the same time every day to minimize the chance of breakthrough. Don't forget, the pill doesn't protect against std's!