Break ups are difficult to go through, and it's normal for both people involved to experience a full range of negative emotions. Even if the split was handled in an agreeable way, feelings will be hurt. One of the main problems you may be facing is that the pain lingers for so long. What you need is help for a broken heart.
As mentioned, feeling bad is a normal response to a break up, but becoming clinically depressed is not. Even if it is normal, it needs to be taken seriously and treated by a qualified medical professional. You need to be careful because a lot of your friends and family will just assume you "have the blues" because you have broken up. That may be true, but it could be that you are actually depressed and need help. If you aren't sure, then it is always better to err on the side of caution and make an appointment to see your doctor.
Assuming you aren't depressed (or that you are being properly treated for depression) there is help for a broken heart. Perhaps the most effective thing is also the hardest. What we are talking about is giving it time. As time goes on the wounds start to heal. Of course the painful emotions can be hard to bear and you don't feel like waiting for the pain to go away on its own. There isn't anything wrong with wanting to speed things up, but try to find reassurance in knowing that your broken heart is only temporary.
Forgiveness is vital to curing your broken heart in a timely manner. If your ex wronged you in some way, then you need to do what you can to forgive them. The worse the offense, the harder it will be; but the worse the offense, the more important it is for you to forgive. Forgiving n ex can actually be much easier than forgiving yourself. The funny thing is that you don't have to be at fault at all, and yet you feel as though you did something wrong. Of course, there is always a chance that you were the guilty party, but whether you were or not, you still need to forgive yourself if you really want help for a broken heart.
Even though you may feel like crawling into a corner and never seeing the light of day again, you need to get out and live your life. Call up some friends and go out, visit a favorite spot or go on a quick getaway; whatever it takes to get out of the house and experience life. It may be tricky at first, but do your best to have fun.
As you can see, there really is help for a broken heart. Now, these tips are only the beginning, and they will take some practice. However, as you find other tips and follow through on them, you will find that you are steadily becoming more and more happy.