Three weeks post miscarriage help!!

I Lost the baby sometime after Christmas but didn't find out till New Years and didn't pass the baby until the 14th. I saw the doctor on the 16th and had blood and an ultrasound that showed everything was good and back to normal. I blead for a few days then we had sex again without protection and have been since. It's been two weeks since we tried the first time and hubby made a joke that I'm acting pregnant took a test and got a faint positive like my last baby. My hormones were really low before I passed the baby and the doctor said they were back to normal after the miscarriage. I'm not sure if this is left over hormones or if I'm going insane..I can't have a positive this soon right??? I found out with the last baby when I was three weeks along....has anyone else went through this???