Good for you for taking a short ride.
Depression is difficult. It's so hard to understand why the things you used to love don't even stir an interest anymore. I'm so glad you're doing the medication AND counseling route. It really will make a difference.
Your SO will probably notice a change in you and in your moods before you do.
Take short rides as you feel like it. Take walks or anything else you may feel like to get moving a little. Sometimes just sitting outside can help...
I have depression that can be almost crippling if I don't catch it early and get my meds adjusted. The death of a parent can definitely send you into a tailspin, as can work stress and many other things.
Hang in there. It will get better.