I too have dealt with the harsh words of people. I am sensitive, it cuts me to the core. It has affected me for days, broken me down, driven me to tears and made me wonder why and how people can be so cruel.
Then I stopped and realized that the person that has the courage to say mean and hurtful things really has no courage at all. It is a mask, a facade they put on to hide the pain they are in. Some people find strength in hurting others because it makes them feel powerful over that person. It makes them in control of your thoughts and emotions.
It is not easy to move past and you should never force yourself to move on and forget. You should allow yourself that pain and hurt because in the end, it does make you stronger. It may take you time to move on but allow yourself the time. Just know that the person who writes or says mean and hurtful things to others are not happy, they are miserable and misery loves company. Those people are toxic because in no way is it ever okay to be mean and hurtful to another.