Started off great - now the opposite

Has anyone had the experience on this where the first few weeks were incredible - almost a miracle. From being snappy, tired, depressed and horrible to be around, I became really creative, active, cheerful, alert and thought 'finally, this is the drug for me!'

After about the four week mark, things have gone the opposite for the last few. I have lost all of that energy, am getting very depressed and anxious and am SO, SO exhausted

I wonder if this is common? I am also on Lamictal and wondered if they could be working against one another.

Is this familiar to anyone?