Single on Valentine's Day

I know there's a lot of people that are single on Valentine's Day but I just feel like i don't know what to do. I feel like no guy likes me or wants me and no girl likes me or wants me. All my friends have boyfriends and I'm the only one who has no one. I usually get invited to things by my brother and this time he invited my cousin (has a girlfriend) on a double date and not me. I just feel like crying myself to sleep every time the thought of not having someone there to hold me and give me their attention comes up. I'm just so lonely and I want more than anything in the world for someone to love me like I love them. I have friends that care for me but they also have their own problems. I just don't know how much longer I can wait.