4 days late

Jessica

So last period was Aug 6th and I had mid cycle spotting from 21-27 now 4 days late on period feeling exhausted emotional grumpy with lower back pain sometimes also crazy heartburn when I never get heartburns.. Anyone experience this type of thing? I took a test on the 27th and it was negative but after a few hours it turned into a faint positive but Idk if it was actually positive or evap/indent line. (Pic attached)