You just hit 80, meaning your gear is probably crap. Facing players who generally 2shot people with your gear, it's no surprise you're getting owned. I'd suggest to wait untill cata, gear up with everyone else and have fun.

Vs melee: stagger your earthbind totems, so press 1: char1 drops one. press 2: char2 drops one, etc. Then after your drop a totem, they'll get entangled. IWT, move backwards, Flame shock -> lava burst and /wave. 4 magma totems + fire nova's will also do considerable damage.