Early symptoms???

Hey girls, so I'm due Af on 4th of dec but glow has been slightly inaccurate lately anyway, I finished Af on 5th of this month and went on my honeymoon the same day! We were obviously bding all the time but I had spotting about 4 days later? Since I have come home I have been super naucious, tired and pretty constipated which is driving me crazy?!! Mood swing have been pretty bad but...I haven't physically been sick nor do I have tender breasts etc? It's too early to test but surely I wouldn't have been fertile straight after my period? Is that even poss? Any advice? Thanks xx