Thanks for posting your query.
From the information you have provided,
Possibility of a
pregnancy cannot be ruled out completely.
As you are not breast feeding and its been well over 3 months after CS , you can or would have ovulated anytime.
Ovulation or egg release precedes periods.
Its also common for the first few periods to be irregular.
As you have had multiple negative home
pregnancy tests and the fact that you have had irregular bleeding, its best that you consult your gynaecologist.
Blood test for pregnancy can give more information.
Its unlikely to be due to CS complication.
In any case, its advisable that you consult your gynaecologist before coming to any conclusion.
Hope this helps,
All the best. Take care.