rear main seal or oil pan leak

[cameyer]

I have had a small oil leak on my 64 k10 and it has been getting progressively worse. My leak is coming from the back of the engine and is dripping off the bottom of the bell housing. There is also oil dripping from the 2 larger bots at the back of the oil pan. The oil is also all over the starter front drive shaft and oil filter. I have wiped all the oil off to try and trace the leak but i have no clue how to tell if it is the rear main or the oil pan. Can anyone help me figure out what is causing the leak?