Advice please ladies

So june was my last period. I am currently 2 and a half weeks late. As you can see i had sex one of the days glow said i was ovulating and my last period was shorter and lighter then normal. I hadnt thought twice about it maybe being implantation bleeding? I have taken 2 tests the first had what looked like the start of a line but decided it was a faulty line because the following test was negative. That was about a week ago. I have a appointment with my primary in a week and a half and plan to get tested then if i havnt started. I mainly want to know if what i thought was my last period could have been implantation bleeding?