Coll, everything you have said points to two things in my opinion, low oestrogen and progesterone intolerance.
First of all, if you didn't have a history of depression and it started 10 years ago this would suggest the link is hormonal i.e. dropping oestrogen levels. If you felt like your had flu on the continuous combined HRT then this suggests you are at least sensitive to the progesterone part of HRT. I felt like I had flu when I was on the pill years ago and I had a constant nasal drip.
The good news is that you are nearly there and are already doing the right thing by taking 100mg Utrogestan vaginally for 7 days each month BUT in my opinion, your are falling over on your oestrogen levels and not getting anything like enough of it. I used a similar patch to you and it was completely useless and so much so, I might as well not have bothered using it at all - blood tests revealed that my oestrogen level were pitifully low. I would strongly recommend you immediately switch to Oestrogel (you simply rub it on your skin) because from my experience, it is far more effective and also very flexible in that you can easily adjust the dose up or down and it kicks in very quickly. It was only when I went onto the gel that I had a breakthrough and finally rid myself of all menopause symptoms.
The problem you have now is that (probably) your are very low on oestrogen and suffering the effects of Utrogestan which is a very bad combination. You could try adding another 50mcg patch to see if that lifts your mood, you have nothing to lose but ultimately I would switch to Oestrogel and start with 2 pumps everyday and then perhaps go up to 3.
Please don't give up on HRT, it sounds like you really need it. I agree that HRT is not a cure all but it is a 'cure most' if you get the dose and type of HRT right.