Johnny is exactly right. If you are carrying felony conviction on drugs, and you have met the requirements of your given sentence or probation, the next action is up to you. It is your responsibility to live as a normal citizen. You might go before a judge and show the hours of documented civic service you have given and have that count as an honest and sincere effort to prove your no longer affected by the illegal drugs. I have seen in the past where that can help in getting someone's record cleaned up. Of course, first, you need the documented service and you then have to ask the court if it is enough, and if not, what more can you do to show your sincere desire to restart your reputation and record.
There is a term in the apartment business called "Drug Free Housing". What this means is that a tenant can be evicted on the first sign of drug use or sale or manufacture to sell. It happens every day in the business. Some people still think the apartment business is old school, where drug dealers can exist and not be bothered. This is now false. Once found they are rooted out immediately. This is why your drug charges are keeping you out of the rental assisted housing. Also some people don't think apartment managers will run background and credit checks. Again, false, we do and we find this stuff.
My hope is that you will take the action and get your record expunged of the drug charges on it. Until you do, it is going to affect you in every area of your life.
This will include getting jobs, renting assisted housing, and other areas. I personally wish you good luck in the future.