How have emails on another account ended up on my orange account?

[purepurple]

I am confused and would appreciate any explaination anyone has to offer.
I have an orange email account. I have a college email acount that I access through the college moodle. They both have different email addresses and are not connected in any way. I have not changed any settings or done anything differently.
So, how come when I looked at my orange emails this morning, I had emails that normally go to my college account? I just don't understand it.

There is usually a facility on email accounts to automatically forward them to other email accounts. If you haven't done that, and there's no one else who could have done that (and why would anyone? I was thinking maybe you'd been hacked, but I can't see any sinister motivation in forwarding emails!), then I'm baffled.
Can you log into the college account and see if the forwarding thing has been set up?

As far as I can see, the forwrding facility hasn't been set up. My orange account is on my list of contacts though. Have I been hacked and my emails are now going to all of my contacts? It's only college stuff, like job vacancies and student union stuff. Still very bizzare.