Being as I'm a lifelong cannabis consumer, I only get a small feeling of paranoia after I haven't partaken in awhile. But I do remember intense feelings like that in the early days.

The best way I can express what happens (only my opinion based on experience) is that all of your psychological baggage (anxiety, fears, etc.) seem to be enhanced when you get high. It doesn't last very long and once the bullcrap is flushed from your psyche you just feel relaxed.

The best thing for a newbie to do is to be with someone who is an experienced consumer and you completely trust. This is especially true for edibles because they take longer to "kick in" and seem to be a bit more intense and lasts longer. The experienced consumer can talk with you and tell you "no worries", just relax. Oh, and tell you jokes or watch something funny. Once you start laughing at even the stupidest things, the edge is taken completely off and you can enjoy the high!