I got a Margin Call on Silver Future position

When I first talked about "Margin Call" and explained what it means to my girlfriend she understood that someone will call me say something like this: "Peeter, thank you for your money. You don't have it anymore."
The real truth is that no one calls you - just there is no asset anymore and no money also...
I have had two earlier posts on this:

• Silver is going up :-)
• Background story about buying Silver

So what happened?
After writing "Background story about buying Silver" in some moment I changed to Silver future from SLV position. First I bought one Silver Mini-Future contract which was approximately for same quantity of Silver than I had in SLV before, so for 2500 ounces. Then it felt good and I thought - let's take some more risk and I changed to one Silver Future contract, postion for 5000 ounces.

So bacically to make it simple, I put 20 000 USD to my investing account and did these earlier mentioned deals. Today just some moments ago I have 4054,69 USD on my account and no position in anything.

Couple of thing I didn't take into account:

• Silver may go down in price. OK, I read a lot of articles about the price in future... and all those suggested rather higher prices... I even read a realistic article that the price should stay between 15 and 30 USD and hoped for 30 :-p
  As long as Silver stayed above 15 USD I had enough funds to cover this position in my account. Today it went under... at least I see SLV price now 14,44 USD.
  
• I didn't take into account that the Exchange NYMEX will lower the Margin needed... I went in knowing that it is 8000 USD and I thought that when my position is worth less it gets sold automatically. They lowered the Margin needed to 5000 USD and as I found out now it got sold automatically when I had 4000 USD left in my account. Good that I didn't had any other assets on that account :-)
• I had no stop order on place... accually I even don't know how to put this into place :-/

Now I can say this was a costly wake-up call. I better start learning more...

At this point I have the plan to add some funds to this account and buy a new position in Silver Futures when Silver price will go over 14-day moving average or 200-day moving average whichever comes first. So I will at least have some kind of strategy other than buy and pray.

At this moment I'm looking this information at http://www.kitco.com/charts/techcharts_silver.html
And just now I also found out how I can create same graph :-)
Just need to take the information from http://www.lbma.org.uk