plan b advice

i take progesterone days 21-30 to regulate my period, so it should start the first week of every month. february was a shorter month, so i didn’t start until the 7th which pushed back my ovulation days. it says that i am ovulating, but i usually never ovulate during these days and i will still start my period the first week. advice on if i should take plan b? i already bought it, just debating