Ex-boyfriend Has Not Paid Me Back For Rent

I co signed on a lease for an apartment with my ex boyfriend. We broke up and I moved out pretty much right at the start of our new lease on the second year. He was paying rent (but was late pretty much every month) up until the last month of the lease which he decided he wasn’t going to pay. I reached out to him multiple times to see if I could help in any way, because I was co-signer I know I am legally responsible for making that payment as well. He read my messages and never responded, I even called and was sent to voicemail multiple times. I ended up paying the full last month of rent because I did not want that to go on my record. My question is, can I take him to small claims court to get back at least half of that last month of rent, or would I be wasting my time since I was also on the lease?