I just did a search for "testosterone levels going up because of weight training", and it looks to me like the effect is only short-term. However, the way you have worded "as I have tried to up my training intensity" might indicate a combination of a bit of frustration of some kind along with the rise? Just a guess to ponder...

In my own case, trying to exercise very much at all is aggravating, depressing and makes me "snappy" because of the physical pain I experience.