I had got my period back on may 16, 2020 one day after my birthday so I barely couldn’t have sex because I was on period so it been four months with my period then I waited to have sex so on September 17 and 18 I had sex with my boyfriend on his birthday on the 17th and it was my fertile week he said he nut in me and we had twice and the next day was on my ovulation the 19th , days go by I’m fine and then today I’m having lower little back pain , my Breast is tender me and my sister check it , it been week going on two three weeks and my period is suppose to come on October 3 what should I do ?