Fear of loss.
There are two ways to handle it. First, simulator, Second small size.
Before you start, get your act together
You need to have a decent system edge and rules that fit your personality. You also have to come to terms with the reality that you may not be suited to trading. You may need to find something else to do. In your place, I would resolve to give it everything I had, knowing that at some point (you draw a line in the sand), I would have to make the decision to stop.
there are many good simulators. Try ButtonTrader.
You can use it to overcome the fear of pulling the trigger and to work the kinks out of your position sizing and money management system (You do have one right?)
Once you have practiced and you have some idea of what to expect from your system, you should trade small size, not to make money, but to desensitize yourself (you have become phobic about this). You want to enter and exit a number of times and see for yourself that you can handle it without trauma. You need to learn to handle spikes, news, and even breakdowns.
During this time, you should be adding to your account size, so that when you do trade "for real", you are not undercapitalized. This is the one thing that traders insist on doing that always kills them. Don't trade undercapitalized.
If you approach the work in a methodical way, you will be successful. If not, you will surely lose whatever money you have to trade. From my point of view you need to put it on the line and find out who you are. A while back, a coach named John Wooden said something about sports that applies to trading as well. "People think that competitive sports builds character, it doesn't. Competitive sport reveals character. You have it, or you don't".
You may want to find out where you stand sooner rather than later.
Good luck,
Lefty