What's going on that makes you perceive there to be a spell influencing you?
When speaking of curses there are a few different types. So assuming you have had negative, as you say, magic used upon you, letting us know what's going on can help to differentiate between the types.
That said, a simple hex, or string of what appears to be awful luck, should dissipate on its own naturally given enough time, and assuming it indeed is something like a temporary working.
There is an option to of course mirror it back, if you're entirely bent on revenge.
In this case you'd write up and cast a return to sender spell.
And this is all assuming that you've had any type of magic aimed at you in the first place.
Again, why is it you have come to this conclusion?