placebo week

I started bc at the beginning of December and was supposed to get my next period on the week of ny however it didn't happen that way. I got it all last week Jan 18 ( I had brown blood turn into red blood and then eventually leave) so I counted it as my period as my mother suggested. (Btw I know I'm not like pregnant or anything because I have taken a test) But now I just took my placebo pill and idk if I should anticipate a period any time soon or if it'll be like last time. My mom said it's because my body getting used to it but I used to be regular and I loved that so much. Should I consult my doctor or let it play out?