Loss aversion and revaluing a stock

I do not follow GILD so much anymore as some remaining of it now make only 0.5% of my portfolio, but latest results seem to be worse than I have modeled and it seems like a potential example of 'sell at a loss after intrinsic value fell' example.

I'll try to run the numbers when I have a moment, but overall it looks like a good learning opportunity that will probably make me more humble in my projections/valuations.