It's the internet hun.... unfortunately, a lot of very nasty negative people lurk on-line just looking for other people to be nasty to...
You have to consider the source.
Those people have unhappy, hollow lives, and only feel better about themselves by hurting others... many are teens-- remember High school? (*EEK!*)
Their lives will NEVER get any better until they treat others as they want to be treated...
Karma tends to come around--- ya know?
Hang in there-- and report/block them if you can!