I was pregnant with twins and had ZERO symptoms before my beta and even well after my beta with the exception of an occasional shooting pain in my breasts that started about 4 or 5 dpt. It could have been the progesterone - who knows. But my first beta at 14dpt was 1600 and even then I didn't have any symptoms. I felt very normal without any other symptoms. It took seeing the HBs at the u/s to truly believe I was pregnant.
I guess I wouldn't read into symptoms during the TWW. Before IVF I had sore boobs, bloating, and even nausea during my TWW and would always have BFNs.