I don't understand your question. If you had your period on the 20th of last month. Why would you be late today? It never hurts to take a pregnancy test if you are unsure but I wouldn't waste my money until you are at least a week late if you think you could be pregnant. If you are trying to get pregnant I would start taking prenatal vitamins. Cut out anything that might be harmful along with alcohol, meds and hot tubs.
why dont you tell us if your late. when is your period due? and the only way to know if your pregnant is to take a test, either when your periods due or missed