I claimed 0 instead of 1 on my W-4 and now I barely get anything back on my income tax.?

Claiming zero results in the highest amount of federal income tax withheld, and therefore the greatest refund. If you want a high refund you could change your W4 to have additional federal income tax withheld, but why would you want to? The lower your refund the more you have to spend throughout the year rather than giving the government an interest free loan.

changing to 0 you should have had more income tax withheld, not less

and you should be watching your pay stubs as you receive them to see if enough is being withheld, and if not contact your payroll dept to find out why

Your statement doesn't make sense. Claiming zero results in MORE tax being taken out of your check than if you claim1. Did you have more than one job? Did you have income from sources other than w2s?

Yup to late to change it for the past.... You need to change it at work, change it from 0 to 1.... this will at least make sure you don't owe .... When you claim 0 they hold out just enough and some times not enough... go in peace... God bless