Has my email account been hacked?

[moosemama]

Earlier this evening I had a text from my dm telling me to check my email account as my Sdad has had a suspect email from me. Checked it, no sign of a hack and assumed it was spoofing again, as I've had that before. Sdad not convinced, as he was worried someone had access to my contacts/address book, given it ended up in his inbox. Reassured him that I don't keep contacts, precisely for this reason, only to check and find bloody Yahoo have changed their set up and since they last upgraded you have to go back in and opt out of it saving every email address into contacts, so I did have contacts and he was one of them.

Then I checked my other two email accounts and lo and behold - I've been spamming myself, which can only mean one thing - someone does have my contacts list.

The odd thing is, my account hasn't been accessed from anywhere other than my own computer at my location. Nothing in my settings, privacy, security has changed and there's no sign at all of anybody getting in there. Plus, when you look at the original messages, the emails are actually coming from the Netherlands with my email address as spoof cover.

I've checked I haven't been pwned as a result of Heartbleed or the MN hack and have different, very secure passwords for everything anyway - and I never click on spam.

So I am totally confused, how can they have my contacts to send spam to, but not have actually got into my account.

Obviously I have changed all my passwords, yet again and ramped up my security/access a level and am now running a scan to check for malware, but it all seems very odd to me.

Any thoughts, suggestions, ideas gratefully appreciated.