Apologise without the 'but'
"I'm sorry, but I was exhausted" is a defence with an apology stapled to the front, and everyone hears it that way. Say the plain version — what you did, that it was yours, that you regret it — and stop talking.
"I'm sorry, but I was exhausted" is a defence with an apology stapled to the front, and everyone hears it that way. Say the plain version — what you did, that it was yours, that you regret it — and stop talking.