PMS Symptoms and only 4/5 DPO?

Right before AF is due I get extremely tired, crave nothing but junk food carbs, and cramping. AF doesn't even start until about May 3rd, and I'm having these symptoms now at 4/5 DPO. Is it too early to be having these symptoms? Or could this be a good sign. I know implantation doesn't happen until about 7 DPO. I just wonder if anyone else was in the same boat and got a BFP or is in the same boat as I am now