Don't go off your pills until the end of the pack, even if you're spotting. You will really throw off your cycle. The only exception is if you miss pills more than two days in a row. If you missed a pill for a whole day, you are supposed to double-up (or take it as soon as you remember). If you miss two pills, you have to stop and then start a new pack. Read the package directions as to what to do with your specific pills in case some of these things happen. But just missing it by 3 or 4 hours, that's not an issue. Just take it when you remember and do better next time.
If you are nervous about getting pregnant, you can always have your boyfriend wear a condom, especially if there is *any* chance at all of an STD transmission. Pulling out doesn't really do very much, especially if you aren't on the pill because pre-cum can have sperm in it. However, if there is no risk of STDs (AT ALL--be sure, this is your life we are talking about), you should be fine as long as you take the pill at the same time every day. A lot of my friends set their cell phone alarm to remind them. It makes it easier.
Personally, I skip 3 months at a time, just because I really don't like getting my period. I had spotting at first, but it went away after the third time I skipped.
If you have any more questions, re-post and we'll do our best to answer your questions.