I don't really feel the need to tell people that I'm clean of drugs.
Why don't you want to tell others?
I don't feel like it's their business to know.
Good on you for getting clean. If you don't feel like sharing that information, then you can save it.
I think they are going to treat me weird if they found out.
I highly doubt that they think you will be weird for becoming clean. I'm sure they would celebrate you making the effort to no longer do drugs.