The best thing is to accept that he is no more this will help you open your heart and move on with life. You are young and you have a great life a head. He would want to see you happy in life so try and overcome the pain of losing him.
michaeljax is right. youll never forget him but you should be happy, and he would want you to be,,,, so when your ready try and start something fresh, just date dont jump into anything too fast, cuz it could happen and if it ends bad that wont feel good. have fun, but it might take a long time. take your time and good luck.
^ not necessarily true that things will only get worse if you do not get professional help. I had a girlfriend who passed away on Jan. 6th a few years ago and things will and do get better. It isn't something you can just dwell on for the rest of your life, you have to know in your heart that you loved then the best you could and know they loved you back and eventually you have to accept the reality of things. Remember him the best you can without putting yourself in a bad place and don't ever let anyone take what the two of you shared and built in your lives away. Just know you have to stay strong and move forward. It is also helpful if you can find someone who you can be close to that is supportive to you in every way when it comes to these feelings.