2 days late

Ab
2 days late on my period, tested twice and came back negative, experienced what I thought was implantation bleeding on the 17th and 18th and now I don't have any period symptoms just headaches. Is there anyway I could be pregnant and it's just too early to show on the home pregnancy test? Im so confused. When I was spotting I had like tugging/pulling sensation in my stomach which is supposedly a symptom