TMI Period? Or Preggers?

Michelle
Hi since my TFMR in Jan (due to T13) my cycles have returned...
My first one was bang on time last month, but only lasted 3 days with very little bleeding, very brown and very light! I expected this as I had have an ERPOC in Feb and the hospital advised it can take a while for your uterine lining to return to its pre-pregnancy thickness.
So now I'm having my second period (I think), but it's a day early... I had some usual PMS symptoms but my period (which has always been really heavy) is almost nothing guys! Day two and I'm wearing panty liners with just a smudge of brown for whole day. Dark red/brown when I wipe! I'm getting dizzy spells, smelling smelly things, sweating profusely every night for the last week and hotter than usual everyday! I took a test yesterday - BFN... 
What is goin on??? Thoughts and similar experiences appreciated!