I had microfracture on the medial femoral condyle (MFC) two weeks ago, so I've been reading a lot about the rehab. In that video of Dr. Steadman's lecture (at the link in this forum) he says that patients are smart and know not to do too much. He says if your knee feels perfect at six weeks, you should go to weight bearing, but if it is still painful at eight weeks, you should stay on the crutches. In your case, it sounds like it could just be pain from not having used your muscles for seven weeks.
You said you weren't allowed to do stationary bike or swimming yet. Dr. Steadman likes to start these within two weeks, the bike without resistance and deep water exercises in a pool. We'd all be interested in what your rehabilitaion has been so far other than nonweight bearing.
My foot gets red when I'm standing up or sitting. I don't really feel it, but if I touch it with my hand it feels cold. It isn't so bad that I'm concerned.