ok...

well from the graduation thing, going off dreams are supposed to be representing what is happening in the sub-conscious (which may or may not be true, but which seems accurate most of the time) i'd say that in some way you regret not being able to go and get your diploma with everyone else... even if you're shy and don't like being in front of everyone, there is still the shame of being behind your classmates.

And as for the clock sound... i don't know what time of day your clock makes that particular sound at, but perhaps you associated your graduation with a particular time (say 3 o'clock) and then you woke just before 3 and then your clock rang the hour. so it would just be pure coincidence then but it would look related, wouldn't it?

yeah, answering a question of 'why' can not always be answered, even though it sounds so simple... sometimes 'why' something happened doesn't matter all that much anyway, it's more what can be done about it now (depending on the circumstances).

As for the feeling... you mean like a feeling of vague unease and like you are slightly different and singled out due to have a weird dream, and like something might happen? Or something else?