Post your part.... Use the Advanced Editor link in the upper right of the dialog box.
It looks like you are talking about sketches, not drawings. Drawings are slddrw files in SolidWorks.
You are working in a part file (sldprt) and are editing a sketch. Not trying to be a pain, just helping with your terminology, it will help you get better answers to your questions.
I either started a new sketch, or the problem went away after exiting then re-entering the sketch. The problem is intermittent, and I am not sure I could locate the file anymore. Thanks for your help!