Stopped working after a year?

Hi there.

I have been on 40mg of Prozac for about a year, in combination with 100mg of lamotrigine to help treat bipolar 2 and pmdd. When I first started, it was great. I had so much more energy than usual and really felt like I could actually enjoy myself and get things done. The past couple months, my depression has been coming back. I have really low motivation, feel so tired, get way more anxious, eat more, etc. is it possible for Prozac to stop working? I'm seeing my doctor later today but just wanted to know if anyone had a situation similar to mine after being on it for at least a year.