On birth control pills, have safe sex with spermicidal lubricant condoms, always paranoid about pregnancy on late arrival of periods. How can I get rid of this habit?

I am 18 years old and i have been on birth control since i was 15.When i was 15, i only took it because it made my periods alot better but now that i am older i use it for the pregnancy prevention. I messed up my old pill pack this past month and my doctor switched me to a new birth control called Nortrel. I have been taking it for 2 days so far and i havent noticed any sudden change. Whenever my boyfriend and i have sex, we always use a condom(spermacidal lubricant kind), and im always on birth control and he never ejaculates inside of me and the condom has never broke because we always check afterwards. But whenever we do have sex, we have sex for only 5 minutes because i am always so paranoid that something is going to happen. And even when we have sex and everything checks out good in the end, I always still freak out when my period comes along, even when my period isnt late. Is there anything i can do to not be so paranoid or can you talk me through this. I really want to have sex and its not that my boyfriend is pushing me, its my own personal issue because i dont want this to follow me through my entire life.