19 days late on period HELP?!

Here’s some back story. Last month I had my period first week of January sometime then I had another one two weeks later. Both lasting 5 days and equal heaviness which was just moderate. Nothing out of the ordinary. (Except having two periods was weird). Now I’m 19 days late from calculating based off of that second one last month. I took a pregnancy test around day 10 of being late and negative. I’m a year post partum and was having regular periods around 6 months PP. but out of the blue that double period happened in January now everything seems whack. Has this ever happened to anyone?