Having no closure at the end of relationship can be overwhelming. I invite you take this time to work on yourself. Improving yourself. Having a healthy lifestyle. Doing something you love and distracting yourself productively. This will help you to look past your problems.

Nd had replaced me in one month he was in some other relationship by all these i cant get over that ..... i was soo soo depressed i was feeling low nd wht should i do to over come

It's highly acknowledgeble that you kept your self worth above your relationship. Betrayal of trust can be hard to deal with. But try giving more importance for yourself,your worth. Try to divert your mind by something you love to do. Pamper yourself.

Should i leave contact from my boyfriend from all social media

That is a decision you have to analyse and take. Ask yourself will staying in contact with your bf would be healthy for you to move on?.

In a relationship, if one person loves the other more than the other, it doesnt work. You can't forget those 4 years but you will have to accept that if he can live without you, you definitely can. You will have to learn to live with the fact that some people are just temporary. Even if theyre in your life for like 4 years. And they're not worth it. There are like so many people out there in the world. Initially youll be disturbed. But youll be even more if you keep thinking about it. Keep yourself super busy. Be career oriented. And the satisfaction youll get at the end of the day with a successful career, will be worth far far far more than a boy who broke your heart.