weird e-mail anyone know what this could mean? has my computer been invaded?

[Linnet]

I've just logged onto the computer for the first time since Christmas Eve and the first thing I did was checked my e-mails. there is an e-mail in my in box from me? it has my e-mail address and it has a not very nice subject heading. It is my exact e-mail address not one that looks similar.

I haven't opened it and it was sent last night at 25 minutes past midnight and nobody was on the computer then.

What could it mean, has someone hacked into my computer? could it be a virus? I don't give out that e-mail address to just anybody.

Can anyone advise or give me suggestions? thanks

It's just spam - delete it (or report it & then delete it) - doesn't mean anything sinister.

I get loads which say they are From myself. They aren't of course, the spammers have just faked the e-mail header (the bit which says To/From/ReplyTo).
Ignore it, it's spam. It must have got through your service providers spam filter. If your software has the option, mark it as spam, then delete it.