Most women don't get clear symptoms until after HCG kicks in at implantation, but there is a massive progesterone surge at conception which can cause symptoms. These can often be mistaken for signs of AF or vice versa, but it's possible to get quite clear signs from conception. I know this because I get them myself. These are my symptoms this week and I'm 99 per cent sure I'm pregnant because of them...
1dpo and 2dpo - hot, light headed, low energy, exhausted, fluttering at pubic line, blocked nose, sore boobs
3dpo - headache, nausea, sore boobs, light cramping
4dpo - nausea, exhaustion, stretching and pulling feelings at pubic line, sore boobs, no appetite, small amount of creamy cm
5dpo - light headed, hot, nausea, sore boobs, cramping, no appetite, headache, thirsty, increased urination, small amount of creamy cm, emotional, waistband of jeans really uncomfortable on stomach
6dpo - metallic taste in mouth, very sore boobs, backache, headache, sharp pain on left-hand side (implantation?), pressure feeling, loads of clear cm, nausea, small BBT dip, problems sleeping, very hungry in night. BFN
7dpo - sore boobs, nausea, headache, loads of white cm, blocked nose, BBT back up, hunger, low energy, absolutely exhausted, pressure and cramping, spotty chin, lots of saliva in mouth. BFN