Do i have a small bit of OCD?

i cant stand posters being crooked on walls there is a clock at my school that is up crooked and it just drives me insane. when ever i feel a little bit sick or if something like my writs or neck hurts or if i find a freckle i think im going to die of cancer do you think i have OCD??? also my little brother cant stand eating crackers unless it is perfect and not cracked or anything. he also has to have his lego toys perfect and he can tell if there is the smallest detail missing. do u think he has OCD too?