Be sure to check out this website... Welcome to Dive Wise - the Freediving Education Initiative see the safety info & video.
Get some freedive training if you can afford it... you really can't afford not to.
Chad
What Chad said...and also what ILDiver said. Never dive alone, especially not if you are trying to push yourself. Let it come to you slowly until you take a proper course.
Sounds like you've got the bug, enjoy your new addiction.