Irregular flow or pregnant ?

So to my females with irregular periods like me I have a few questions, I have always had a irregular period and last month my period was more like when your period is coming to a end and it’s the darker reddish brown color but it only lasted 2 days and I didn’t think much about it till this month my period is 2 weeks late and I normally wouldn’t think of anything but I am sexually active and have this undeniable feeling it might be more, I have been doing a lot of looking around on google and came to the conclusion it could possibly be implantation bleeding so I took a few pregnancy test and they have all came back negative, so I’m unsure rather I might be pregnant and just tested to early or if my period is just irregular like usual, any advice would be nice.