Is it possible to feel the effects of Synthroid after only 5 days?

I started taking 50 mcg synthroid 5 days ago after two years of TSH levels between 4.0 and most recently 5.9. I had been havinting and light bleeding for three weeks prior to starting the synthroid which was preceded by 3 months with no period. Now 5 days after beginning the synthroid I started my period and am experiencing very heavy flow and more severe cramps than I've ever had in my life. Could this be a result of the synthroid after such a short time?