implantational bleeding is actually not that common. Not sure what the stats are but I had it with my dd and not with this pregnancy. Dont worry!
You don't need symptoms to actually have a viable pregnancy. Only around 30% of women will experiance implantation bleeding. You're still early in the pregnancy, so there's plenty of time for you to develop symptoms in coming weeks. Good luck and I hope you have a good nine months!!
I had no symptoms at all til I was 11 weeks pregnant. So no obvious implantation symptoms :) don't stress!
It's ok not everybody gets implantation spotting. Are you getting any blood work done? Try to relax but I know it's hard esp in the beginning phase of pregnancy. Congratulations and a happy and healthy 9 months.