What we mean when we say " I cut my hair yesterday".
What native speakers think we did yesterday.
When we want to talk about something that someone else did for another person or for us we have to use the structure:
Have something done =
subject + HAVE + object + V3
If we say:
I fixed my car. This means I fixed it myself.
If I paid someone to fix it (or just someone did it for me) we say: I had my car fixed.
HAVE + object + V3
I had my car fixed.
We can also use 'subject + get + object + V3 '. This has the same meaning as 'have', but it is less formal.
I get my hair cut once a month.