Hello Thunder,
Welcome to the forum, and it's nice that you feel comforatable enough here to ask us for advice on such a tough situation.
What the many posters above have said regarding getting some professional couselling help is right on the nose. This is the sort of issue that therapy is designed to help with. It will take some time, but there will be a true positive change with some work with a pro.
The suicide of a parent is very difficult blow, and one that is far different from other sorts of suicide loss that a person may encounter in lifee, due to the unique parent/child bond that exists.
You describe a sense of loss of self, a sort of a draining of identity which has not returned. This fits with the trauma of loosing a parent this way. A person whom you deeply cared for, and had many connections with, behaved in a way that was totaly unexpected, and tossed into question all the things that you felt you knew or believed regarding this person. Such a blow has deep effect on oneself, and you are sadly suffering from the effects of that first realization now. It's normal to have this happen, and not your fault that you feel as you do.
That you realize that you are not 'yourself' shows that you are making good evaluations of yourself, even while hurting so badly, and it's a major step toward finding your way back to a more satisfying life.
Take some time to find a professional mental health expert and take time to work with them. Know that the first person you work with may not be the right one, you may need to try a few until you find 'the right one' that you can work easily and best with. This process will take some time, but it WILL lead you to a better place.
There are also suicide survivor support groups that can be located with web searches (Online forums, and real world meeting groups) where you can talk about your feelings and experiences with others who can honestly say they understand. If out and out councelling seem too hard, or is not a possibility due to finacial worries, these groups can provide some help that may help you begin to work things out. A professional is still the better option though, and should be the way you first look, using the groups as additional support to that therepy.
You have done nothing to deserve the three years that you have had. Your fathers suicide was his choice. And a choice that no one he left behind may ever be able to understand. It's sad that he also wounded the man you were with his action. But you are still here, and the man you were is also, just tarnished by this dark event. You can recover and have a great life.
Lastly, I'm not a writing rules crazed guy, but please, puctuation, paragraphs, and lower case letters will make your communications with others a lot simpler, and convey things with much greater speed and clarity. We are happy to have you with us in our community, and want to be able to understand what you need and have to say!
Take care,
Myriads