Confused and worried -- help!

Hey guys, been having something strange happening to me recently and would like to hear others input on the matter as to what is going on.

I started noticing this all about over a week ago. I went to a friend's house to play Halo Reach, and his account was silver so I downloaded my profile onto his Xbox. We played Halo that night, then I didn't use my profile till a day or two later when I
was playing Gears of War on my console, and then I haven't used it since till yesterday, instead I have been playing on my brothers Xbox account since it has GTA 5 beaten and an active Netfix account. While on my brothers profile, I always look at my friends
list just to see if any of my friends are online, and I started noticing that it said my profile (Individual) had been recently logged in. I didn't really think much of it; figured it was my buddy accidentally logging into the account. I shot him a text asking
if he has been logging in by accident, and he said he isn't and that he has been seeing it pop online fairly frequently. Right before posting this thread it said that my Xbox account was last online about an hour ago, even though my Xbox has not been online
at all today, and no one has been home to turn on my Xbox.

That freaked me out, so I changed my password on my account, made sure all of my security information was mine (it was), and then looked at where all the sign ins to my email. Most of the sign ins are from my mail app on my iPhone syncing mail, which can
be identified because it says that the Device/Platform is Windows, and the Browser/App is Exchange ActiveSync. From what I can tell, any time I sign in on my Xbox 360, it says that the Device/Platform is Unknown, and the Browser/App is Unknown as well.

Here's where it becomes weird: Right around an hour ago (when my Xbox profile said it was last signed in), it says that my email was logged into from Unknown and Unknown, indicating that is was from an Xbox, and the location it was from was MY IP ADDRESS.
Like I said earlier, nobody but I was home to turn on my Xbox and sign into my profile, and I have not signed into my profile today.

I'm dead serious about this too. I'm genuinely worried about this. I'm fairly certain that my house is not haunted, and I do not have amnesia or dementia. Usually I would not care about something like this, but I know for a fact original gamertags like mine
are prone to being hacked and stolen, so I'm being extra cautious. Any ideas or suggestions would be helpful. I'm currently thinking that perhaps having it say Unknown and Unknown does not mean that it is from an Xbox? I don't have the Xbox app on my phone
either

:)

 

Achievements not unlocking

So you unlocked this over a year ago and are just now worried about it? I'm not confused.

 

Halo Reach Preview Update Disc

It still says its incompatible, and I have STILL yet to recieve my code.

Im kind of mad, but moreso worried/confused.

 

I'm not really sure what would cause that either, but you may want to look into this as well -
live.xbox.com/.../Protection You can remove your profile from all consoles from that site. So if someone else is using your account on a different console, they would need to redownload
it before using it again, and since you changed your password they wouldn't be able to.

If you are worried someone else has your account, you may want to contact support and have them start an unauthorized access investigation.