Sometimes I feel really sad, how can I stop this?

I am 13 years old, and my parents aren't divorced, I have loads of amazing friends (and three best friends), and I have lots of cool things such as my own laptop and an Xbox 360 because my parents have plenty of money to live on even though we are not rich. We live in a 3 bedroom house (there are the four of us) and sometimes it can be a little cramped, and it is usually a bit messy (not unclean or messy with tons of things tered across the floor), and when I go to my friends houses, theirs is a bit cleaner than mine. We have recently had the bathroom, my bedroom redone, and we are going to get the living room redecorated soon. We are also looking to buy a new house and are close to doing that, but I still sometimes feel a bit sad and annoyed when I see the house in a mess as I adore clean this e.g. when my sister drops a sweet packet on the floor I get really annoyed at it. I think that I may have minor OCD, and I love this to be orderly, so how can I make this better and make my house cleaner? My parents don't have any problems such as being alcoholics or anything like that. Thanks a lot for answering!