Help!!!

How much blood are we talking for implantation bleeding? I never had it with my son. So here's what happened. Yesterday around 4pm I got a real sharp tugging pain in my stomach. Only lasted 10-15 seconds that was that. This morning Iv been to the toilet to find small tiny specks of blood. I wiped a few times to check & the small specks were still there. Is this implantation? I'm due on next Tuesday. Also iv had crazy heartburn & I suffer with hayfever but this morning iv woken up and have a really strong sense of smell. Am I going crazy???