How do I stop being sensitive and crying over past wounds?

Why would you want to stop this? As long as it is balanced and you can function in daily life, crying is not a bad thing. It usually means you are allowing yourself to let go and process old wounds. In any sense it would be way worse if you just held it inside and never let anything out. Being sensitive is okay, you're allowed to feel. If you think it is too much you can always find help in dealing with it. So it is not something you have to deal with alone.

You let go of the past and stop letting it hold you back. Dont let the past somethjing that doesnt exist determine your present.

cry as much as you can and let everything out at once. We often try not to cry but I will advice you to go ahead and take out whatever your heart is holding, then a point will come when you wont cry any more and will move on automatically.

It's really hard letting things go- trust me, I would know. However, that does not mean it is completely impossible. There are several mechanisms and things you could do. For example, journaling is a very popular one. It allows you to let go of all your thoughts without actually speaking it. You could also talk to someone you trust/love. This also works, which is writing things on a plate you don't really want, and then breaking. Or even, writing down your thoughts on a tiny piece of paper, and then throwing that paper in water (be careful not to litter though of course).