When you're logged into your work account (say, in GMail), does the URL contain /u/0 or /u/1? And how about your personal account?

Whichever one says /u/0 is the first one you logged in as, and that will be the default if you, say, open a new tab and paste in a bare link (without /u/ in it).

If you want that to be your personal account, you can make that your /u/0 account by doing this:

1. Log out of all your Google accounts

2. Log into your personal account

3. Click the picture in the upper-right

4. Click "add account"

5. Log into your work account