I too had a complete hysterectomy 11 years ago and had severe mood swings at about 2 months out from my surgery to the point of being suicidal...as the estrogen that had been in my "fat cells" had been depleted and although they did have me on a patch it was not enough for my needs...so it took a while to sort it out but I am ok now...my symptoms are tolerable most days with just the estrogen patch...
I would recommend going in and getting a Hormone blood panel run and if your hormones are low (which they should be with having had hysterectomy and now being 51 years young) tell the Dr. you need some help with hormone balancing...they will most likely want to offer you and anti-depressant but this will only mask and not actually deal with what is going on...so it's ok if that is what you want to do but I would try getting some bio-identical hormone therapy going and see if it helps before the anti-depressant...our hormones affect everything so don't let the dr. brush you off as "normal at your age" or normal because you had a hysterectomy....if so, seek another dr. until you find one willing to help you feel well! You might also have them check your thyroid...good luck where you are now is a miserable place...I have been there and it can be better!
If your ovaries were removed in 2005, it is surprising you have just recently started feeling this way. If they were not removed, this could be symptoms of natural menopause or a more severe menopause if the ovaries are shutting down. Studies show that naturally menopausal ovaries produce hormones until at least age 80. Hysterectomy with ovary preservation can cause the ovaries to die which increases risk for a number of health problems such as heart disease and osteoporosis.
Estrogen typically alleviates the symptoms you are experiencing. I am in surgical menopause and depend on estrogen to keep me emotionally stable as well as help with a number of other symptoms such as insomnia, memory, focus, temperature regulation, etc.