I would not worry yet unless you are losing copious amounts of blood, have heavy clotting or extreme pain. Your hormone levels may have changed due to improved thyroid function and possibly even improved liver function. I have read women can get pregnant for two or three years after their periods stop, so I assume we still have our hormones working somewhere. You may be growing younger before our eyes and your system is reacting like it did in the past.
You might want to get this checked out if it continues or gives you problems, but hopefully it is just a hormonal surge from your cleansing and supplementing. I also had my periods end about two years ago. However, I still get PMS almost every month (well, that's my excuse for feeling rotten and sometimes acting like a b---- or bursting into tears). I will also get cramps, but no flow. I will be staring the IP6 sometime this week-as soon as it arrives. Hmmm...I wonder. If anything happens, I'll let you know.