Abnormal period

My husband and I are trying to conceive after being on birth control for years. I stopped my birth control about 5 months ago and have had my period every single month on the date it’s expected except for last month I was three days late. This time around I was supposed to start on June 19th. I had all my “normal” symptoms leading up to it and actually around 11pm on the 19th had discharge that was light brown to indicate that I started my period. I’ve been wearing tampons the last four days and each time I go to change it only the tip has the same light brown discharge and it’s a small amount. I took a pregnancy test yesterday that came back negative. I don’t know if this is an irregular period or if I’m pregnant.