I am 50 and am 2 weeks late for period. There is now a little bit of old blood for 2 days but no "real" signs of my period beginning. Is this the beginning of menopause or should I be concerned?

It could very well be the start of things... while not likely, you would want to rule out a pregnancy though by taking a test. Your doctor can do some hormone testing to determine if it is likely perimenopause.