Thanks for your query.
The altered bleeding pattern that you are facing is due to the double dose of morning after pills.
Even a single dose of morning after pills produces irregular and unpredictable bleeding.
If you have taken 4 negative pregnancy
tests, chances are extremely remote that you would be pregnant now.
Mostly the problems you are facing could be attributed to erratic intake of emergency contraception
However, please consult a gynecologist to confirm the diagnosis.
Also, please switchover to a reliable method of birth control in the future.