How do you get over a bad break up or failed relationship? He's the one who broke up with me, without giving me reasons at all...he just became cold and distant.

Then he is the one with the problem, not you .  I would say you are better off without someone who can't even have the decency to tell you why they want to end the relationship.  It's never easy when a relationship ends, and it must be even worse for you , when you have never been given the reason why, but it really is true that time is a great healer .  In years to come , you will think back and wonder what you ever saw in this person.  You will meet someone who will appreciate you, so good luck for the future .

I am struggling from a break up-we broke up last year and it was pretty much the same situation as you.
Ive been texting a couple of lads since and have one relationship but it didnt work, cause he was my first love i will always feel for him - like theres times i feel really strong and i think im over him but the feelings keep on coming back.
It all depends on how serious the relationship is, the best way is to try and take your mind off him by talking to other lads, try and find someone else <3

Usually when that happens it kinda means they were cheating or are already with another person... But you just have to give it time you cant be over a person in one or two days it might take awhile. If you feel the need to cry thats fine its better then keeping it all bottled up insidee cus then you explode at the people that mean the most to you. Write poems that might help :) but int he ehad keep your head up if he sees it down hes gonan think your weak and most likely attempt to take advantage..

Forget about it

He's obviously hiding something from you... Talk to him.

It sounds like someone else has caught his interest.  It probably was a good thing that he left you alone in order to save you from future disappointments and heart aches.