Effects Fading?

I’ve been on fluoxetine for almost a year now. Started with 10mg and gradually increased to my current dose (40mg). Things have been fine but this past week it’s like they just completely stopped working. All my depression symptoms are back. Has anyone experienced this? This has actually happened after about 3 months on every dose, which has caused my doctor to increase my dose each time. I have an appt in a few weeks so I’m going to talk to her, but I wanted to see if this has happened to anyone else. It’s like things are great and then they stop working. So strange.