Why am I upset about something that should be a good thing

I have an interview for an industrial placement next year at a really impressively top-notch place.

This upsets me for the following reasons:

1) It's on a Tuesday, which is practical day. This means I must now e-mail the malicious convenor (who already knows I'm a dolt) to ask if there is some way I can do the work that I ought to do. Theoretically I should be okay since it'll be mostly set up for the next few weeks.

2) I am going to miss a practical for a position I probably won't get.

3) Even if I do get it this means changes, which I hate. I do not deal well with change.

4) Not to mention I will have to tell my housemates that they need to get a different housemate. Not a conversation I look forward to having.

So I haven't even told my mother about this yet, even though it would make her week, not least of all because she suggested I go for this position, 'cause I know she'll be all happy about it and I'm just not in the mood.

None of this is helped by the fact my hormones are all over the place, and I don't know if I want to break down and cry or just break someone's neck.

In short- arrrrgh!