This thread amuses me... as almost every single answer is right, but almost every single one is wrong too.
OP - Overtime laws vary wildly from state to state. For instance, in the last state I worked, if you worked over 8 hours in any given day, all the hours past the 8 mark were overtime hours. However, in the state I currently live in you can literally work all day (24 hours) and not get a single bit of overtime (with a few exceptions in various industries), all that matters is your work in a week.
For another example, some states consider the shift, not the day, so if you work from 6 pm Wednesday to 6 am Thursday, in some states that is 4 hours of overtime b/c it's one shift, even if it's separate days. However, other states only care about the day. Nobody can tell you anything definitively without information on where you live, sometimes even the city you work in is important info (though that's rare). Target can have it's regulations/guidelines, but the actual rules/laws vary wildly.
P.S. - Google is a good resource for this info, though it'll take a little digging. Also, don't give your personal info out on here, Spot can get mad.