Four day missed period

Erica
I have type one diabties and I've noticed for about the past week or so my blood sugar has been extremely high like 400-500's. My sugar is normally around 300's and not really in the 400 or 500's. But it seems like every day i can eat something small which will shoot it up that high for example I had a bowl of raisin bran about 11am yesterday and then a fun size bag of chips around 3:30pm(before I ate the chips my sugar was 260) then at 5:45pm I tested my sugar and it was over 500. I am four days late and I've taken about five pregnancy test which all have come back negative. Could my blood sugar being so high block the test from coming back positive?