Hi Ttal and welcome!
I was addicted to oxycodone for 2 years also, and I stopped using in December. I am at 5 months out now, and I feel pretty good. But I gained about 40 pounds while on oxys due to immobility, partly due to the orthopedic surgeries I was recovering from at the same time, but I have just recently been getting back enough energy to start exercising again. Plus the weather has been crappy.
At 3 months, I would hope you are feeling better, but truthfully, a lot of us got hooked on opiates in part because they make all your worries and depression go away. For awhile. Of course, this is fake, and when tolerance builds, the effects are not as good, and eventually they don't really help your depression at all. In fact, the oxys weakened my natural resilience so much, I thought I would never feel normal again.
So, any residual depression you may have had to start with is still going to be there in recovery. I don't do NA or AA either, for a number of reasons.
I hope you can get help for your depression and anxiety, if that it is. Getting clean does not mean you have to suffer from medical illnesses like depression that can be treated with non opiates.
Good luck, and don't give up.
FT