help please 😬

hi, teenager here who was planning to have sex with her long term boyfriend for her very first time thursday (two days from now). however i missed my birth control both friday and saturday and usually when i miss my pills i do not take them when i remember because it can cause me a lot of nausea. sunday and monday were fine, took my pills, but today (tuesday) i am bleeding... is it just spotting or am i now on my period??? would it be gone by thursday??