Thanks to East Coast weather, my connection tonight in SFO (PDX-SFO-BOS) has dwindled to 46 minutes. I know UA can't do anything for me since I'm still above the (ridiculous) 25 minute MCT at SFO but am worried about being stuck at SFO for the night on what is basically a MR involving a full day's stay in BOS. Am I fretting too much? If I get stuck at SFO, can I just head back to PDX on Saturday instead of heading all the way to BOS and back?

I'm also under the assumption that I should probably not check my bag anymore.