I use hushmail for hobbying, and when I logged in today I was puzzled by something. When I clicked on where it says recent activity there were a few dates & times listed that I know are incorrect and I wasn't signed in at, but my IP address was showed. And I'm single and am the only one who uses my computer, so I'm a bit concerned with how this could have happened. Well if anyone has experienced this or can offer any useful advise I would very much appreciate it. Thanks

There is always the possibility you got hacked somehow.  Can you correlate the times times you mentioned with anyone else being in your home?  I'd definitely check your computer for anything malicious and change your password for hushmail at a minimum.

Thanks for the advise, and I did scan my computer using windows defender, which showed one malicious file. The weird thing is a couple of the times listed were in the middle of the night, and I haven't had anyone in my house recently. And all of this took place within the last week. I also want to add that I am always careful to delete all emails sent to and from the ladies I have contact with, and am very seriously considering canceling my hushmail account.  

I was using gmail, but I heard the security with hushmail was better, so if anyone can shed any light on that or recommend another email service please reply or send me a PM. Thanks

Hushmail is far more secure than gmail, yahoo, etc. in that all email is encrypted and it's too cumbersome for most automated hacks to work.

You should have a passphrase that is easy to remember but extremely difficult to guess. I don't think there is an option to 'remember me' so if your account is showing activity, it could be any number of things.

1st - download and run Malwarebytes. Windows Defender is not enough. Deleting emails only protects you from someone looking over your shoulder or snooping in your account (good to do but not enough) -- by the time you open them, it's too late if someone already had a keylogger or other malware on your machine.
2nd - change your passphrase and watch for unusual activity. If you see it again, contact Hushmail and ask for advice/insight -- it could be server activity or something like an automatic 'check for email' request (similar to how Outlook or Gmail checks every x-minutes).
3rd - If there is activity, create a new Hushmail account and see if it happens again. If it does, consider doing a clean install of your PC -- that means wiping it completely and installing a fresh operating system, and then reinstalling each piece of software you use. Do not reinstall a backup OS unless you know 100% it was clean at that date -- that could just lead you right back to where you are. You should of course back up files/documents first.
4th - Use Firefox or Chrome with Adblock and other security/privacy extensions (this should probably be second in the list). They take a little time to learn to use but will keep you far safer than most Anti-Virus software. Norton, McAfree, etc. are useless -- worse than what they supposedly protect you from.
Last - even if you follow all of the above, don't send personal information such as your real name or credit card info via email, ever.  

This all falls under reasonable precaution. Remember that ip address you mentioned? It would be pretty easy for LE to track it back to you if they wanted -- it's simply not worth it in the vast majority of cases for them to prove it is a specific individual.

If you want to be even more safe, only use a burn phone (purchased with cash, minutes topped up with cash) with internet/browser and never turn it on within 2 miles of your home or office. For most, it's not worth that level of paranoia

The way you describe it sounds as if someone may have remote access to your PC. Or they may have infiltrated your home network. some precautions you could take would be to change your windows passwords and avoid using an account with admin privileges. Also change your router password. And if you live in an area where there are a lot of college students living nearby you should change your router password at least every month. With the right equipment it is possible to sniff out your routers password in a couple of hours but if you keep changing it they may look elsewhere for free internet access. If all else fails, just unplug your router when your not accessing the web.