confused...much needed insight!

So today af (according to glow) is 2-3 days late. I began light spotting (light pink to brown) 4 days ago.   I usually spot before AF arrives so I assumed this month we weren't successful. But this spotting was different I usually never have spotting more than 1-2 days before it af comes full force. I've also been cramping like period cramps. So I decided to test this morning with FMU and got a BFN :(  ...unless someone sees something. I used some store brand test and strips I got online. A few months ago I was 8 days late but did not have spotting at all. Does this mean I am out for the month? Should I get another brand & test again? I mean obviously I don't know what to expect when ttc but the spotting is throwing me off. Help, I need insights!