10 days late

So I'm now officially 10 days late and still getting negatives on the hpt. This is only our 2nd month ttc. my periods are very regular, if they are ever late it's only by a day or two. I'm concerned that I'm just psyching myself into thinking I'm pregnant when I'm really not. I had a little cramping today but no AF and no other pregnancy symptoms. How much longer should I wait before getting a blood test?