If I were long GC based on the previously mentioned premise (found here) then I would be out and waiting for a new long trigger.
Based on the 4-H chart (below, right) your first warning was the Fast Line crossing the Slow Line, your second warning was the fast line turning negative (red) and your final warning being the strong momentum after the 3rd fast line negative reading. Given these "signals" if you were trading based off of this chart and it's signals, then you may have been able to exit at break-even . I understand that can be perceived as hindsight bias, but these are the signals/triggers I look for personally.
The setups I include on this blog are used in conjunction with the 3/10macd and the criteria I ascribe to it as a way to alert me to an existing condition of price. The key concept to take away from this blog is that I try to anticipate what will happen on the higher time frame by using a faster time frame to trigger the trade setup. I do not trade a "system" I use two indicators to clue me in to price conditions. Please read the Disclaimer located in the sidebar of this site. I can be contacted via email at firstname.lastname@example.org
I am always open to questions, comments, or suggestions on how to improve this blog.