If you had sex three weeks ago, and the blood tests are 1.2 and 1.6 now, your missed period was not from pregnancy. "Signs and symptoms" don't prove pregnancy, they can come from an ovarian cyst or something else. Think of it logically -- if your hCG level was high enough five days after the sex to actually stop your period, it would certainly show up on blood tests now, and would be in the hundreds. Other things can stop a period besides stress and pregnancy. If no period comes in the next couple of weeks, see your doctor.
It's possible you're SUPER early. They usually say you're NOT PG with anything under 5ml though. I'd say wait 5 days and test again.
HPTs can occasionally give an incorrect result, but the blood work is pretty conclusive and it says you are not pregnant. Have you had sex since? If not, I'd say definitely not pregnant.
If you have had sex since the Thursday three weeks ago, there is a slight possibility that you ovulated late and are pregnant but it is too early to tell. In which case, wait at least 14 days from THAT time and test again.