A Long explanation.
I wouldn't worry about it. One testicle is 100% as functional and capable as two. One testicle has 350 million Leydig cells (i.e. test producing cells). Those cells are capable of producing far more testosterone than your body could ever use or in fact handle. The control of how much they produce is regulated by pituitary hormones primarily Luteinizing Hormone (LH). Thus your brain works like a thermostat determining how much testosterone is in your system at any given time and adjusting the levels as needed by signaling the testis to produce testosterone when needed. The gist being your testicle is more than man enough for the job. Now if you use AS for extended periods of time what happens is that your brain thermostat (hypothalamus) says "hey fellows wait a minute we are producing way too much juice- turn down the faucet". Thus your testis begins to produce less and less testoserone. It will not stop completely because there is an inherent minimum production that it will maintain. But, if this goes on for a long period of time, then the body's response is to say hey what do we need all those Leydig Cells sitting around on their bums for- they aren't doing anything so get rid of them- no welfare system in this body. Thus you could have minimal shrinkage in the testis which would be hardly noticeable to you physically if at all. Also key is that when you stop the AS the testis would once again start building up the production staff so to speak. So to answer your question- No you have not been hurt in any way by this condition. At 6'2'' 195 I would say you owe that testicle some serious praise- he is pulling his weight. I can think of know real risk to your testis from AS but of course that is my opinion and it is your nut. Just curious though, you say you were born with only one- that is very rare. Was it the case that one was resected at birth due to failure to descend or did you just only have one. If that is the case, I hope that you have had studies done (CT Scan) to ensure that you do not have an undescended testicle in your abdomen. The reason I ask is that there is a very high risk of malignancy (cancer) in undescended testicles. Anyhow hope this helps.