Hi Trevor,
I’m sorry you are having difficulty accessing the store. There is a lot going on here that I’ll try to explain.
Some ISPs change the public address assigned to internet connections when they detect a change in the protocol from http to https. What happens is, you are logging in through http at ExpressionEngine.com When you click on “My Downloads” you are taken to a secure area over https. If the public IP address changes, the session that was started when you logged in becomes invalid. That causes you to be logged out at the store.
The reason this can appear intermittently is because not every ISP does this. So, it may work flawlessly at the home or office, but not at the coffee shop.
You can contact you ISP, or try through a different connection and let us know the results.
Thanks!