1) sometimes when for example my sister has a freind round I start having like this really strong feelings even like I want to Mary her! Even though I don't know her !
So I love it when she brings home freinds, and whenever I can I hang around with them.
Is this crazy? Is anyone else also like this?
Aren't you from a chasidish home?
It sounds like you have a strong urge perhaps stronger than it was for me at your age but it is not "crazy".
2) I've started hating going to mikva, it's disgusting! To see naked people, and also I'm too embarrassd. Is anyone else like this? Or am I just different?
Hmm... What changed? Why do you all of a sudden feel that this is disgusting? But no, you are not different. Some people are more private than other people.