I need help...? Lutherans please..!?

Okay, im a Christian, lutheran, and 14 years old. I really want to understand and be close to God, but i don't feel like i am. I've had depression...it gets better every once and a while and sometimes i feel really guilty cause when im feeling good im usually missing church, not praying, etc. And then when im feeling down i usually am constantly in prayer, read the Bible every night, and im always asking God for help. i don't know what im doing wrong. i feel very detached from Him right now and don't know what to do. And to add to this, i have a friend that likes to make fun of people that go to church and talk about it a lot. (she's not the reason im falling away.) I felt a huge lump growing in my throat when she asked if i went to church and if i liked it, and i said no. i can't stop being her friend though because i don't have many friends and im very lonely. Please help me. Im lost.