Tunnel, I'm afraid you missed the point entirely. Or almost entirely. Yes, the "exercise" is partly to develop an understanding of the nature of probability in trading, of loss, of being sensitive to what the market is telling you.
However, there's a "Part A" that you missed, which is the development of the system in the first place. Taking 20 or 25 or 30 trades that are not prompted by a consistently profitable trading system/strategy is useless. You have to initiate the development of the system, THEN test it by implementing these trades, then re-working it, then trading it again in a closed loop until you have something that is consistently profitable.
So, as suggested earlier, the problem is not you but your system, or rather lack of a system. Contemplating your navel isn't going to be of much benefit. Of greater benefit will be to buy a package of lined paper and a box of pencils, a cheap/free software program (preferably with replay), a cheap/free data feed, and several pounds of coffee.