Ultimately, the one thing I learnt from a broken heart is to give it time to heal. The first few days will be hell, the first few weeks will be tolerable, the first few months bearable. So it goes on and on, and before you know it, a year passes, and then another, and then another. But the pain will always be there, unfortunately.
Crying is the best way to let it all out. The frustration, anger, pain. Just let it all out. I used to cry myself to sleep every night, and eventually it stopped. I feel better. There's nothing weak or embarrassing about crying, its just an expression of emotion. So why hold it back, when in times of sadness, all we want to do is cry? Let your eyes be puffy, its all right to cry.
Aside from crying, talk about it. One thing it does help with is that it helps you cope with the reality. Talking about it means that you're acknowledging the truth, but more than that it means a lot to share your pain and sorrows with others. It lets you know that there are many people in this world who care about you, no matter what. So talk about it. Whatever it is. Your worries, sadness, grief, anger, resentment. Talk about it, someone will always listen.
If ever you find a day where you can't seem to talk to anyone, write about it. Put it all down in words, be it in a diary, a letter, or even a blog. It helps you remember, what went wrong, why you made such decisions, how much pain and hurt you feel, why you can never go back to how things were, all of it. Expressing yourself might not lessen the pain, but it can always take away some of the weight weighing down in your chest.
Then, get yourself busy. Be it work, assignments, workout sessions, as long as its healthy. And the key to doing this is by having great company. Go out with your friends more, watch funny movies, go bowling, swimming, and have fun while you're at it. This will take a lot of effort at first, but you'll get used to it eventually. You have to remember that things are over, and you're trying to get your life back on track, so you have to start making yourself happy. Family and friends will give you support, a shoulder to cry on, and hugs, whenever you needed it. Don't be shy to ask. They'll always be there for you.
Give yourself a break. Its okay to be sad, to be fragile, to be hurt. We are all humans, we made mistakes, we learn from it. And that's what makes us stronger.
Just know that you're not alone in this.