Why does my OCD or whatever i have do this to me everytime i start a new hobby?

last week i started a stamp collection. yesterday i was looking at the over and sorting them out by year. i looked at some of them and i laughed to myself and said jeez it's like all you see on the stamps is people. then instantly my ocd kicks in. then i start to wonder is everystamp made have pictures of people,or are some made withouth people on them. so i go thru my collection and find one with just a building on it. no people or nothing,plus i find another one that just says usps on the bottom and then it says 10 cents. so i'm like ok so i guess they do make them without people. so i put them up and plan to come back latter to rework on them. as soon as i get up to go,i get like a weak stomach feeling in my stomach. and i go back to the book and open it and look at the same two stamps i explained earlier,the buliding one and the 10 cent one. so i'm like ok no people. then i leave. 2 minsutes later i feel funny and have to go back to view them again to make sure that they do make them withouht people on them. so then i get to wondering,do they make them with people in them. so i go back and grab 1 stamp that shows people on it,it's a stamp of george washinton,and a stamp of some soldiers and says armed forces. then i have to look at the ones with the building and 10 cent. so i'm like ok,some have people,some don't.then i walk away 4 mins later im' back looking. and today i had to leave the house,so in order to not feel funny i take the 4 stamps with me and look at them every few mins. so then i start to think,well maybe i'm just seeing things,so now i have to take them out and ask strangers on the street,if they see any people on the two stamps,and if they don't see any people on the other stamps. then when i get home i start to wondering if they make any with animals. and etc. it's like this everytime i start a hobby. it goes good for a few days or weeks,then something stupid comes up and will drive me nuts,and i'll have to wind up stoping the hobby cause if not. i will drive myself crazy over the stupid stuff. what can i do to stop making myself care over stuff like if some stamps have people,and some don't have people,just pictures of flowers,building,cars,animals and no humans in them. i refuse to give up anymore hobbies,so what can i do??