As people have already said, relaxation seems to be your main TECHNICAL problem rather than the voice itself. Tension can play havoc with the voice and can do long term damage. There are numerous relaxation techniques you can try to solve that one. The ones MacColl devised for the Critics Group always worked for me, and once mastered, could be gone through in a few minutes. The simple act of dropping your shoulders (which, with me, always rose to ear-level when I was tense) works wonders.
However, if you are reading the posters while you are singing, I would suggest that your problem is not technical, but lies in your concentration and your involvement with your songs. Perhaps this is the source of your problems which you need to work on.