Hi lisauk - I agree with Hurdity, that is a LOT of prog, especially with the Mirena as well. On Utrogestan I feel exactly as you describe, I couldn't imaging how I would have felt taking it daily!
I had a Mirena fitted a week ago, and tbh I haven't felt this hormonally stable for several years - and it's been almost two years since the late peri hell hit me. However, it's early days, so I am monitoring myself closely without being obsessed if you know what I mean?
If you've been happy with the Mirena until now, and it's due for replacement, why not have it done and try without the Utrogestan for now?
Also, weaning off your ADs as you are, which one are you on, and are you taking it very slowly? ADs such as paroxetine and venlafaxine need to be tapered very gradually as the withdrawal period can be dreadful. I was on 5mg (yep, half the therapeutic dose) of Paroxetine for 11 years and tried to stop it many times - it ended up taking about three months.
Good luck with it all xx