HELP please Spotting/ can I be pregnant/ so confused!

I have not had my period this month.

I spotted once beginning of the month then spotted another day towards the middle of the month. Yesterday November Roth I started my period my today December 1st it's over. I took a test on thanksgiving day and it showed not pregnant.

Why is my period so messed up this month could I be pregnant and the pregnancy test be wrong?

Also this may be a stupid question but I had an MRI done today on my spine lower back, if I was pregnant would they be able to see it? Please ladies I need HELP.