There are many variables in a blood test workup and variations in results are normal. And on top of your input, don't forget the lab techs. I have heard that testosterone levels are higher early in the morning.
I have blood work done every year and keep the results and compare them. Two years ago my PSA jumped my from previous year's result. From 1.2 to 3.8. Freaked me and my doctor out. He wanted to start medication. I knew that my lifestyle hadn't changed, I was experiencing no sign what so ever of BPH(not that that is a sole indication of prostate health) and no indication during my digi prostate test of enlargement and so I retested. Came back 1.2. Go figure. Same results the last two years.
If your testosterone continues to decline on a yearly basis, than you might consider some remedies. But in a two month span, I wouldn't worry. More importantly is how do you feel? Tired, restless, unmotivated? How are you doing in the gym? Are your maxs harder to get to? If you are sleeping good, are having good workouts, strong morning wood, and want to get laid, you're fine.
A yearly physical and blood work are a must. And don't forget that prostate exam in addition to a PSA test.