I think I can control spirits. Help!?

I had tampered with a Ouija board over spring break, and now it seems like I can control the spirits. I went to a camping trip with a bunch of kids from my school, and we spent a night all just singing calm songs. We were all standing, and I decided to joke around and "call down a spirit" and cast down my friend Rose. As soon as I called it down, Rose falls down unconscious. At first I think it's just coincidence, so I decided to try it again. I called down a spirit on my friend Emy, and as soon as I did, she falls down, but this time she's spazzing out on the floor and having convulsions. This isn't the only time this has happened though. I've told spirits to do certain tasks for me, and I'd come back to that location with the task done. I think somehow using the Ouija board has connected me to the spirits, and I'm a little freaked out. Any suggestions to what I should do?