Sounds like mirtazipine isn't suiting you, it is one of the best for older people though. With all that has happened in your life, and losing your kitty too, being overwhelmed is a normal natural emotion and might be appropriate right now. Feeling sad and emotional isn't necessarily a sign you are depressed, flattening of emotion definitely is. Why not allow yourself a week or so to feel whatever needs feeling. Accept you have a right to be sad, lonely, or whatever and see how you are this time next week. I had a terrible christmas and new year, cried, punched pillows, stated at Dave's picture and realised I was so bloody angry at my rubbish luck with partners. Still tearful now but I had put on my 'surviving face' so long I had got stuck. Yet I feel so much better than four months ago when I hit crisis
point, Its been so long on medication that levelled me off (7 years since the change before ) I had forgotten what human feels like.