Capital Gains on Duplex Househack turned full rental

[Ryan Matthews]

Duplex purchased in 2012, occupied one unit until 2015 and then rented out the other side. Moved in with my girlfriend in 2015 and the duplex became 100% rented. No new property was purchased. Considering selling the property to lock in equity appreciation gains since it's impossible to find a lender willing to take a 2nd position on an investment property at a decent LTV.

My question is this:  Since it was my primary residence and I occupied it for more than 2 years, do I pay capital gains? I'm trying to understand my tax liability and any other expenses outside of my realtor's commissions and depreciation recapture. 1031 exchange is not an option as I am not purchasing a new property at this time.