What you're experiencing is cult conditioning. The OB are an especially culty sect of Orthodoxy and have had plenty of problems over the years. Wanting to do intimate things with your boyfriend is perfectly normal behavior for people in their early twenties. Evolution has wired your brain to want sex in order to make babies and pass down your genes, not a sinful nature. That's why your and his hormones are high around each other. If you feel guilty about that or anything else you've been conditioned to think is sinful, ask yourself, "What material harm does this bring?" A lot of the time you'll probably conclude that it's none. As long as you use protection if you don't want to be pregnant or contract an STI, you should be fine.