Q:

Simple sentence or compound

I got up and opened the door.
Whether the given sentence is "Compound" or "simple". 
I am really confused to distinguish between them.
Kindly, give me some hints to explain the difference between them.

A:

I don't know who I am and don't care.

Compound.  Two independent clauses, either both with the same subject, even when in one of them the subject is implicit not explicit, or different subjects: 

I made dinner and she washed the dishes.

Complex. One of the clauses cannot stand alone as a "statement":

I don't know who I am  ...  when  the alcohol | drug | spirit-guide is talking.

