No symptoms, late implantation bleeding

Hi girls, Tested this morning 17dpo at 4am and at 7am. My period is three days late. I have no symptoms at all. My first pregnancy i had massive sore boobs but ended up in miscarriage. So this time i am expecting some sort of symptoms. At 14 and 15 dpo i had some brown blood discharge i thought my period came but no blood after. And just have sensitive nipples but thats pretty much it. I still can’t believe this. Is it normal to not feel any symptoms? Is that possibly mean low hcg level?