Is the questioner's action correct when she sees a few drops of blood, then stops for a day or two, then resumes seeing heavy menstrual blood accompanied by pain, and prays during that period of cessation?

Your action is incorrect. Rather, it is obligatory for you to stop praying upon seeing blood, even if it is a small amount. When the bleeding stops completely and you see the sign of purity by dryness, perform ghusl and pray. Then, if the blood returns, you revert to the state of a menstruating woman. The period of purity interspersed between two blood flows is a valid state of purity, during which all rulings pertaining to pure women apply to you, according to the preponderant opinion.