What Is The Treatment For Headaches And Blurred Vision In The Right Eye?

Recently, I went to get a new contact prescription since I had run out of contacts. I ended up getting the same prescription as before but a different brand of contacts. I am now getting headaches and my right eye is more blurry than my left eye. I used Encore contacts and now I have Air Optix. My vision was perfect with my old contacts and now, despite getting the same prescription, i get headaches and blurred vision. What could be the problem? My prescription is (-2.75 for left eye and -3.25 for my right eye.)