I have a Canon Rebel EOS T3. Great camera but some problems of late. I put a polarizing filter on it. Not sure if this is where my problems began but some pictures in normal outdoor light have black corners on the top left and right. Secondly indoor pictures with flash are noticeably darker.

Of course the simple answer is to try and remove filter but it is on real tight and am afraid to force it- ant thoughts-suggestions? not to sound like a complete moron but clockwise or counter clockwise to remove?