1 day late on period. Neg blood test and hpt. HELP!!

Kalyn
My so and I have been trying for a baby since we had a missed miscarriage at 9 weeks on July 5th. I had a d and c done on July 6th. Had mild cramping for a few days and minimal bleeding. Waited for 2 weeks to go to my check up apt. Took tests to see if my hcg levels were going down. Finally on August 1st got a negative hpt on digital and dye test. I got my period August 8th and it lasted 3 days. I did opks after that and had positives on August 20-22. I'm currently 1 day late on my period and I've been feeling really tired.. A little nauseous an had mild cramping that goes away and comes back since Sunday on my right side by my ovaries. I went to the dr today for a blood test because I've gotten really really really faint lines on hpts and the blood test came back negative. Could I still be pregnant and be too soon? Has this happened to anyone else? Any advice is appreciated!