I, too, have slacked off on the walking - I skipped today, 'cause my left knee has been complaining
when I go up stairs. It helped, tho, to ease the guilt when I saw it was raining! I didn't notice any pain during yesterday's walk (part of which has a decent hill), but for the rest of the day, I knew my knee wasn't right. Only slightly swollen, and not excruciating, but a distinct twinge. So, I'll take today off (going shopping, but no hills or stairs), and try again tomorrow.
Dang-it, I thought losing twenty+ and walking would help, not hurt!
Just gotta keep the numbers down, and keep losing.