Getting confused with ATC order...Violation?

Hello-

I am a student pilot. I was out flying solo today and was instructed
by ATC to fly a heading of 210. I thought he said 110 and I flew on
that heading. He then told me it looks like your going the wrong
direction i need you to fly 210. I got a bit locked up and said 210.
I ended up on 210 but I really kinda got "mike fright".

Anyway, I just wanted to know if this would constitute a violation and
if I might receive something in the mail, etc? He later told me to
"resume own navigaion" and I did not know what that meant...I asked
him if I could do my airwork and he said resume on navigation meant I
can do anything I want.

He did not ask me to call a land line or anything like that, though
when I requested to change to my CTAF as I had the airport in site, he
said frequency change approved and squalk VFR when I am on the ground.

Any thoughts?
SD