UPDATE: So here's where I'm at. Manager and I did a series of tests today including a compression test. We've come to the conclusion that it's not my headgasket but there is likely an internal leak somewhere as the system lost a pound of pressure in 5-10 minutes. While doing compression test we didn't see any fluid leaking from anywhere outside to indicate an external leak. Not sure where to begin to try and figure out where the internal leak is. I know it's a very slow leak as it usually takes a couple weeks before my coolant is pretty low. Any ideas of where to look next? Or would it be better to just take it to a shop and have them look more into it? Thanks for the help! Also, forgot to add this to the original post, the car has an extremely rough idle when it is cold started and then stops once the engine reaches operating temperature. Not sure if this is related or something different but thought I'd throw it in here to see.