Fusion surgery is difficult even for people who are strong and fit at the time of the surgery. Hopefully you are able to gently exercise - small, short walks - that you gradually increase over time. I had T12-L4 after an accident and found that walking several times daily was the key to getting stronger and tamping down the pain. I had to wait until 12 weeks to do PT, but once you start it, you will begin to feel much better. Be sure to find a PT specifically skilled and trained on backs - backs are very sensitive and a PT needs to not push too fast or it will backfire.

Surgeons do not do a good job of preparing people for what they are going to feel post-surgery. In the past, we were given opioids and not told much about how to care for ourselves. Sleep, healthy food, daily gentle exercise and patience with yourself and situation will help.

As of yesterday, I am 8 weeks past T10 to L4 fusion. I know that I am improving a little each day, but I agree it is so slow and I can’t believe how much soreness and aching is involved with getting up from a chair or getting out of bed every single day.
I can tell that walking is helping. It stretches and strengthens the muscles as your body moves, and I can feel it when I let my arms swing a little.