A bug in passing the Dead Money (Fallout: New Vegas)

When passing DLC Dead Money,when you get down to the main storage, I have gradually reduced health,at first I thought it was because of the clouds(playing on hardcore+difficulty latest) .Had every 15sec to inject a stimulant to not to die(I thought it should be).I went through the Dlc and when I got out in the Mojave began to play the Intro final. During this scene, I died a few times(tried to boot) in the end introduced the tgm..Thought that because of the smoke,I went Out on the Mojave and why the health without tgm still continues to decrease,replay don't want to do?