Signed for a house but now im unsure! Help!

I've recently just signed for a house (even though my parents said it was financially better for me to move home) I know they are right but I didn't want to move home. So anyway I've signed for a house with three other girls. I know one of them well and the others a little bit. I'm going through a fair bit at the moment, and im not sure if this is why im feeling unsure or because I really am unsure. They all have boyfriends except me, and Im worried im going to be the one left out (theres always one). I don't know if I regret signing the contract but im definitely having anxiety about moving in with them.

What should I do and what are my options?

unfortunatley once you've signed the contract if you want to leave you usually have to find someone to take over the tenancy agreement