Weird period

So maybe tmi. For the last two months my periods have been so weird. Last month it was four days late and just brown spotting. Nothing heavy but enough for about one pad a day. Well this past month it's been brown again. It was about two days very light again and then yesterday I had nothing until around 2pm. Then I started getting brown spotting again. Today heavier brown spotting then the last few days. Anyone with similar issue or advice? I've taken a pregnancy test...twice. Bfn.