Menopause Support Group
Menopause is the physiological cessation of menstrual cycles associated with advancing age. It normally occurs in women between the ages of 45 and 55, when the body begins to slow and stop the production of eggs, estrogen and progesterone production decreases, and menstruation diminishes, eventually stopping altogether.

I'm very sorry to hear about your husband's passing, obviously you have been going through a tough time. However I really feel with how are describing your symptoms on here you are menopausal. Please keep in touch and if you do go to your doctor let us know how you get on.
Lack of sleep, poor nutrition etc also have effects, more in some than others.
I can't tell you about definitive start of menopausal signs as it's been a case of me being logical and rational...as opposed to thinking "hey I'm 23 and my hair is thin, must be menopause" or "I'm 25 and sweating like a pig in 70F, must be menopause"...nope I have no idea how long it's been going on for me, just that it definitively is by method of having had several hormonal tests.
I'm sorry for your loss, I can only imagine what you might be going through.
Regardless of menopause hormonal imballances can cause a lot of symptoms that might think you're going bonkers, when in fact it's just hormonal controls stopping you from being you.
You're still in there, and won't be lost to hormonal imbalances and changes.
Hugs