Intense, intense fear during SP

[infinityk]

I wasn't able to lucid dream since the summer because of college and such, but I recently got back into it. Now, I've had a plethora of lucid dreams before, a lot of them were done by simply setting an alarm an hour before my regular alarm went off and then entering SP -> LD. I've never, ever had problems with SP. I always found it fun, but the past 2 times I've tried LD'ing since summer, I feel something in the room is watching me and I get so fucking scared. I can't move (well duh, SP) and I end up shutting my eyes and trying to pull myself away from the evil force and end up just sleeping. Can someone tell me some factors that are influencing this fear? I really want to LD, but there's no way I'm going through that feeling again, it's absolutely horrible I don't think I've ever been that scared in my entire life as I was in my bed, motionless, last night.. haha. Edit: Could this possibly have anything to do with smoking pot? I smoked daily since September and stopped 3 days ago for break.