I had been alesse 28 for about three years up until just over a month ago when my doctor recommended I switch to tri-cyclen lo due to some side effects becoming worse. Over the span of those three years my boyfriend and I regularly had unprotected sex. However, yesterday he finished inside me. I know it's not much of a problem if taking the pill every day at the same time which I typically do (usually within an hour of when I'm supposed to if not right in time). He never came inside me before so I'm a little concerned about the chances of pregnancy because I've switched the pill so recently and we're not ready for children yet. I know there's always a chance but I've read that after a month of switching to a new pill, it goes back to 99% effective. Is this true?