Give yourself credit for the progress you HAVE made.
If you cannot take all 5 (or 10 or 20) flights of stairs, take one flight.
If you cannot hike to the top of a mountain, start with one mile.
If you cannot run a 5K, start with running around the block.
Give yourself grace.
Start somewhere.
Just begin.
Give yourself credit for the progress you HAVE made. You are doing great. Keep going.