Worked more than 20 hours TIER 4 and did thesis correction

I have some questions. I already finished my study in Nov 2013. I did my viva defence in the end of March 2013. Then I did my thesis corrections and submit the final copy to my university early November 2013. My uni said that I worked more than 20 hours per week in the end of May, 2013. I myself cannot remember how many hours I worked as a TA during that particular week as it was in 2013 and now is 2017. My question is, does it mean that I breached the UK immigration law if it is true that I worked more than 20 hours in that week and I was doing my thesis corrections.
Thank you in advance for your help and advice.

intanzz wrote:My question is, does it mean that I breached the UK immigration law if it is true that I worked more than 20 hours in that week and I was doing my thesis corrections.

Yes.