I prayed for years for God to make me straight. Since He didn't do it, does that me He created me as a gay man?

There have been many people in the Bible who have waited on God for years for the manifestation of a prayer. Abraham didn't see his promise come to pass until he was almost 100 years old. Still the Bible says he was "fully persuaded that God would do what he promised"(Romans 4:12)

To be more direct, however, the answer to your question is no. Just because a person prays "to be straight" or to be "changed to a heterosexual" is no indication that God has created someone homosexual. Neither is it an indication that God will acknowledge it or answer that prayer. Understand that there is a right way to pray and a wrong way to pray.In James 4:3, we are told that when we pray selfish, carnal prayers which are out of line with the will of  God, we are praying "amiss". In other words, God does not want just your sexuality, he wants ALL of you. He has always been concerned with the TOTAL restoration of man, not just compartments of life. There are plenty of heterosexuals who do not know God. His purpose is not to change your sexuality, but change you life. Remember the goal is not heterosexuality, it's holiness.
You cannot seek God on your own terms. This is what has created a misguided sense of alienation from God in many gays who claim to have tried prayer to be straight but found it useless. Although the sincerity of the seeker may be 100% true, the manner in which one approaches God is important.

                                  Anyone who comes to God must believe that he is and that he is 
                                         a rewarder of those who diligently seek him. Heb 11:6

I would suggest that you go back to him and offer him all of you. If I were you I would say "Lord take all of me, I'm yours completely. Wash me completely and renew a right spirit within me". I believe that if you pursue him with all your heart, you will not be dissapointed.

                                For I know the plans that I have for you declares the Lord, plans to
                                 prosper you and not to harm you, plans to give you a hope and a future.  
                                Then you will call upon me and come to me and pray to me and I will
                                 listen to you. You will seek me and find me when you seek me with all
                                 your heart. Jeremiah 29:11-13   

What is homophobia?

Homophobia in it's technical sense denotes an "irrational fear of man". The word homo is from the latin genus which means man. Of course because gay language thieves have hijacked anything that remotely shows them in a negative light, the term "homophobia" has mutated to the extreme awful. It's original (possibly well) meaning is no longer recognizable among straight (no pun intended) thinking men and women.
Homophobia is now as deadly as a gallon of anthrax. Enemies of liberty use it as a weapon of intimidation and discrimination to destroy politicians, religious leaders, neighbors, corporate heads, anyone who would dare disagree with the elitist demagougery of the gay rights movement.
The "official" definition of homophibia as set forth by gay orthodoxy is an "irrational fear and hatred of lesbian and gay people that is produced by bias in a society or culture" (via SIECUS). Note the introduction of the word "hatred."

Read a powerful essay by Allan Turner "Homophobia" and the Homosexual Agenda

Homophobia, as well as "tolerance" ,"diversity" would be harmless if left to their original meanings. People are people and have a right to deal with whatever "phobia" they may have, including so-called "homophobia". Christians should resist using this word to describe others because it only fuels the counterproductivity of the gay movement.

Read another insightful article by Patrick Gibbons "Homophobia has become too inclusive"