Truck driving is pulling and lurching

My dodge dakota is pulling from behind then lurching a little when I drive
it and the breaks feel really weird.I've never had a problem before with
the truck and so this is really scaring me. Any ideas as to what it could
be and how serious it is and what is invovled in having it fixed? If you
can help me I would greatly appreciate it. If you have any advice you're
welcome to e-mail me @ nextmiahamm18 (AT) aol (DOT) com. Thanks!!