I'll be honest, unless you're combing your hair with a comb made of magical angel feather plastic than yes you'll lose a few hairs to breakage during combing. It shouldn't be an excessive amount, but you're likely to underestimate your own strength.
I've accidently broken a hair or two and I don't let it bother me. As long as you aren't loosing clumps on the comb or in the shower you should be fine. Also, make sure you're actually experiencing breakage. If the strands have white bulbs at the end than it's shedding, if there are no bulbs than it's probably breakage.
But if you've given yourself a protein treatment within the last 6 weeks-2 months, or a trim, and have kept your hair moist and protected than a few snapped strands shouldn't cause you any worry.