I agree with Bibs.  The problem is probably not the opening since either can be very solid.  The question you should ask yourself is which opening do I better understand the middle game plans, the pawn breaks, etc. so I can find good moves?  You will discover that by deeply analyzing where you went wrong in your own games and looking at some high quality GM games and seeing if you understand (and can guess) the plans and moves.  When you can answer that, you will know which opening is the most solid for you.  Good luck.

I have lost some confidence after some bad games. I want first of all not to lose. What do You think?