If you become more positive, you will relish life more and everyone will enjoy spending time with you. It is not easy for you to change behavior patterns at your age, but sometimes a life crisis such as losing your husband can be an impetus to improve yourself.
I am not certain that you are indeed too critical. I am simply basing my answer on the remarks that those who love you are sharing with you. May Hashem comfort you in this time of great loss, and I wish you hatzlachah in dealing with this difficult situation!