Breakthrough bleeding

So I was doing some research about my abnormally short cycle from 11/26 to 11/28 and found out it was or could be breakthrough bleeding. Where the egg implants but not soon enough to cut off you entire cycle. I have been having a lot of symptoms and even took a test, but it was negative. The doctor stated it could still be too early and to wait till around my next cycle date. HELP!!! anyone experienced this or have any thoughts on this. Much appreciated