So, let me sum up -
Some hacker hacked into my target account
I had my credit card saved with my Target online account
So this guy ordered a $50 target gift card to his email, although it appears to be my own email address
Anyway, Target sent an email notification of the purchase, seeing that I figured the problem, so I logged in and cancelled the order.
pick a tight and secured password
do not store your credit card with any online site
Finally, in case someone hacks your account and uses your credit card account, make sure you monitor your credit card statement, do not ignore small transactions, in case of any fraud , report that to credit card company.