My normal sleep hrs are 8, but for over a month needing10--12 hrs a night to function, this is a heavy loss of precious time, what may be the causes pls?

Vague. With your brief med. History that I see, it could be sleep apnea, and you may need CPAP machine or dental sleep mouthpiece. But there is no way to know unless you see a dr. Asap for a thorough evaluation, history and exam.
Excessive sleep. You may be suffering from anxiety or depression. Consult your doctor for help.