I GOT SCAMMED! DVD Scamm

Wow I never thought it would happen to me, but it did.  And I can tell you its the worst feeling in the world because you can't do anything.  Here's the story:  I went on craigslist and wanted to by E.R Dvds which were worth about $100 and he wanted $50.  I offered $40 and he said $45 because of shipping.  He wanted the money through a U.S postal money gram.  That was my first warning! I immediately replied "How do I know you wont just take the money and run, how do I know this isn't a scam?" so he sends me back a sob story that got to me (god I am such a dumbass) he writes " I wouldn't do that, I just got done burying my son and wouldn't do anything that I wouldn't want done to me god bless." So I send him the money, and he said he'd send it once he gets the money.  2 days pass, and I email and I get no response.  3 days, 4 days, I keep emailing no response. So now I'm skeptical, I go back to the original post and see payment info from our company.  Oh god, now I realized I screwed up.  Now I don't know what to do and I'm out about $50.  Well I learned my lesson and I hope you guys don't do the same.  NEVER SEND MONEY, meet in person!  Unless on ebay or amazon.  If your wondering HE LIVES AT 51 High Court Manhasset NY 11021! NEVER BUY FROM HIM, I am tempted to go to his house and give him a little present.......ugh SCAMMERS!