2002 X5 4.4i, leaking oil, blinking SEL

Hi

I recently bought a used '02 X5 4.4i. A few weeks ago, the truck developed an oil leak emanating from the driver side of the engine (somewhere). The SEL light would come on for a day and then go away for several days. Today, the SEL light began to flash and the car is running quite roughly. Any thoughts? Does this have to do with winter temps? The CCV?

Thank you for any help.

blinking is bad...get it checked-out ASAP!