Implantation bleeding?

Help me!! So my husband is out of town for work... I went to visit July 27th - August 1st.... my periods have recently been all over the place. And I was due for my period August 5 but it came the 10th however was light and only 3 days and when I updated these dates in the app it changed my ovulation date to the 27th! Could this be implantation bleeding? Could I be pregnant? This morning I woke up with a massive headache and felt nauseous after I ate something j felt much better... thoughts?!?! I plan on testing tonight and the next few days... update i did a test and it was negative but it would only be 3 weeks since.... too early to test! I’m convinced I’m pregnant I’m having headaches, backaches, nausea, lightheaded ness, sensitive to smells and I can smell things stronger now ... is it possible?