I smoked marijuana for the first time last night?

I am a devout christian, and have been since birth. I attend church 2 times a week and I am one of the student leaders of my church's youth group. Last night I went to a party with a friend from my high school. At our school, most of the guys and girls are not religious at all and party every weekend. Now this was my first ever party and I refused to drink alcohol. So my friend insisted I smoke some "weed" with him. Next thing you know I was going crazy, laughing my head and saying the most ridiculous thing. I felt like I was loosing my mind. I feel so guilty and I feel like I let everyone down, especially my lord and savior. Should i goto confession and confess my sin of smoking marijuana. Is it even considered a sin? I felt like the devil was taking over me.