Trading and Emotions

I am now at the point where I know good money-making trades but the problem is actually executing them. Seems that all the recent volatility in the market has shaken me up and I am making bad decisions. Starting today I had good positions and ideas for good trades. I executed those trades and then midday reversed course and blew up most of the profits I had made. Don't really know why I did it. I guess there is the fear of losing the profits I had made. But why go short? Anyway the market kept rising through the day and I ended up giving back most of my profits by the end of the day. My trading account and Roth IRA ended up about $500 on the day but it could have been at least $2000 if I had played things right. Only consolation is that this is only 10% of my money. Another 10% is in my 403(b) and 80% in Australia in retirement and non-retirement accounts which I am not actively short-term trading.