Present perfect had we already done this work by the and of the lesson?

We had already done this work by the lesson 

Good mornind, doctor! i desperately need your advice!   -good morning! please, sit down here! what's wrong with you? i am at your assistance. -thank you, the thing is i can't sleep at nights. in fact, i haven't  had a sleep for 40 hours and right now i'm suffering from awful headache.  -oh, that's serious. we need to realise what's the problem and i guess it's connected with your mental state. have you worried much recently? - yeah, my exams are coming up and i'm really worried as i want to get excellent marks. you really think my insonmia is caused by this reason?   -sure! i want you to take some medicine. and please, don't worry that much. try to reduce stress my taking a hot bath or doing your favourite hobbies, whatever that makes you feel better. cheer up, everything is going to be alright!   -thank you so much for your support! have a great day!