If strumming is new and learning the right way is new for you it will definitely do that in the beginning. Believe me every guitar player goes through it my friend! The more you get comfortable with gripping your pick it will get easier. Believe me, I was playing for 15 years and it wasn't until last year that with this school I learned how to grip the pick the right way and I went through the same exact problem as you are going through! And I was even a primary rhythm player with a strong right hand! If you want to, or if you can, posting up a video of you doing it will help us decipher if there is something you are doing incorrectly