Under Exemptions/Allowances, for a single person with no kids and no one else to take care of, what's right?

I have Federal:2, and State:1 under Exemptions/Allowances, is this wrong? I got a significantly lower return this year than I had with my previous job, like as in a few hundred bucks rather than a few thousand... and I'm still in the same tax bracket, nothing else has changed, didn't buy/sell any stocks, didn't buy a home, etc.. the only difference is my old job was in a public university, I now work in the private sector. Is my Federal:2 State:1 Exemptions/Allowances wrong then? Is that why I'm not getting as much of a tax return? Thanks.