Don't get too worked up about it. Let AMCAS do the math for you, don't try to do it ahead of time, and then you won't be sad when it's lower : )
I know that's insane advice to give anyone on this uber prepared, probability calculating forum, but do try.
My BCPM was based roughly half on the "quarter" or "trimester system", and half on the semester system. I believe the credit I earned on "quarters" was translated from 5 credits to 3.7 credits in semester hours, which yes, did mean that somehow that part of my GPA counted "less". Though I can tell you, I worked as hard on the class that lasted 10 weeks as the one that lasted 14, and I think I may have had as many hours in class too.
It will be okay -if you're really close to a GPA tipping point, maybe it would be worth waiting to apply a year so you can take a couple more classes to step away from the precipice.