I been off birth control for a month had a full period at the beginning of this month. Period was supposed to come on the 29th and it hasn't a few home pregnancy test said negative but no period. I have frequent headaches, cramps, bloating and random constipation sometimes.

Of course it is showing negative, you are testing way to early. You need to be at least 14 days late to start testing, so just wait for another week and try testing again, use first urine of the morning always after you awake.

Try a test every week if still negative.