Lot of people avoid trading Mondays. They also trade light or not at all or only in the am on Fridays. Its all to down the risk and reward - no point risking all your money for half the risk. Days which are or are right before and after US public holidays are also likely to be light volume and volatile. For all these same reasons, many traders avoid trading 100% during the mid-summer.
Having said all the above, at any time on any day, using a MA cross-over as an entry signal is a very weak trading strategy.
I have to add that I also think your risk management is weak - it should not be possible to lose such a high % on any day.