Mom is suddenly doing things for herself - why am I freaked out?

Mom has lived with us for a year now. Had a stroke and has forgetfullness and vision problems. Things that she has been asking me to do for her - like buy minutes on her phone and put her pills in the pill boxes - she is suddenly doing for herself and all by herself.

I came home from a small errand to find that she had done 4 weekly boxes worth of pills - pre-breakfast, breakfast, lunch, dinner. Some meals she takes 5 pills. She had done them all correctly.

I'm not sure what has brought about this change and I'm kind of spooked. The doctor did double her anti-depressant about 3 weeks ago and I wonder if that is what is behind this.

I guess I should be thankful. It's just odd.