I thought I was the only person with this problem!!

I can't multi-table for the life of me, mainly for the same reasons that you mention. I just about always screw up in a massive pot that I think I would have avoided if I was just on that one table.

I've been playing for about 18 months also and still class myself as a noob really. I haven't played 100'000's of hands like some people that have been playing for a similar length of time to me. I'm still trying to improve my hand-reading, player-reading and develop my own style / strategies. I think until I get more experience then I'm probably better off playing a single table.