Derailleur issues. Help needed.

Hey r/bicycling, I've just removed and cleaned my rear derailleur (Sram X7), and now that I'm attempting to put it back on, the derailleur arm is tensoining towards the front of the bike, rather than the back (causing the chain to fall loose). It's almost like the derailleur is backwards! Any ideas on what I might be doing wrong?

Thanks.