Look at sheet music that is much easier than your current ability. The first few pieces will probably seem very difficult, but I encourage you to stick with it - reading will only get easier. As you already have 2 years playing the piano, you have most likely built up some skills and methodology to learning music. What you will need to overcome when learning to read music is diverting to familiar processes in learning (such as tutorials and learning by rote), as opposed to reading the sheets. You need to resist any urge to fall back on methodologies familiar to you in order to overcome hurdles encountered in learning to read music, and instead persist in surmounting the hurdle through developing reading skill. In essence you will be learning a different way of doing something you already know how to do.
Build confidence by starting with very easy pieces, hands separately.