Thanks for sharing. Yes behavioural questions can be tricky and we should all get well prepared, esp. those who haven’t been in the market for a while. Overall, interviewing can be very demanding, both physically and mentally.
If you don’t care much, somehow the message will be delivered via body language and the way you answer questions. It is doubtless that employers are more interested in those who are keen to get the offer.
Can I suggest that to get a full-time permanent job should actually take priority as the purpose of studying is to get a decent job anyway. And one can always study part-time while working if you wish.