Missed Period & Negative test

Hello ladies, I’m so confused about my period!!!! I’m 1 week late and I took 2 pregnancy test and they were both negative 😩 yesterday after being 1 week late I spotted only when I wipe I noticed glossy pink and today only a little bit less than yesterday but dark brown and then this evening NOTHING!!!!!! This is the 1st time since I got off birth control in December that I missed my period or I’m late. Ever since I got off birth control I’ve been having my periods every 25 days except this time. I’ve heard of implantation bleeding but wouldn’t my pregnancy test be positive by now if I was pregnant?! I’m super sad 😢 because this might be the beginning irregular periods. Could it be that I my periods will be wack since I was on on birth control for 4 years ?! What do you ladies think?!