Pregnancy on combination pills

I have been on combination birth control pills called Tri-Lo-Marzia for 1 month and 5 days now. I have a decent amount of sex with my longtime boyfriend and I was just wondering about pregnancy chances. We don't use condoms during sex and he pulls out before he cums, but, I take my pill every night at exactly 10:30 so there shouldn't be much concern right? The only thing I can think to worry about would be precum. On that same note are the effectiveness rates for birth control if he cums inside you or just from having sex in general, say including things like precum? Finally, I have had trouble getting wet when I'm aroused since I started the birth control which I have read is a decently common side effect. Does anyone have any idea how I could fix that, besides lube? And does anyone have any natural things they use for lube? Currently I use coconut oil because it holds up well and smells good as well as not effecting my vaginal health. Thank you in advance.