Please help!!!!! did somebady access my machine remotely?

I've used Terminal server for a month and everything looks OK. but last week is really strange. I remotely accessed my office machine at my home, when I first trying to logon, the error message appear:

"The remote session was disconnected because another user has connected to the session"
and what is even strange is that my email (outlook) is opened! I remembered very clearly that I did turn my email off when I left!

The following day the same error appeared. and one of one sensitive file is opened. it's just so suspicious!


Which of the following is possible:

1. Terminal normal manitenance. (Can the maintenance open my already closed email or file?)
2. Domain administer came in to check my email. (That's terrible)
3. Other person with my login name and password come in. (Terrible too!)

Expert please help to explain !!!! thanks so much!!!!

I have had similar thing happened to me when I was disconnected from my remote connection with the message that another user has connected, even though I know at that time of the night there will be no one in the office.

Is there a possible security issue here?

If anyone can help with this issue that will be very appreciated.

Thanks for help in advance.