Your biggest lead of the game was 12 points, for 7 seconds, in the middle of the first half. If you consider this a bad loss you haven't been playing very long.
Which you haven't.
I've blown 20 point halftime leads more than once. And come back from 20 point deficits. In this case Porter's foul situation probably helped you some in the first half, but you were still very much lucky to have a fairly small halftime lead. There's no reason to expect to be lucky again in the 2nd half.