After you file

So you already filed and received your refund? Not sure what you mean by "my Martial credit" I assume that is a typo for marital credit--whatever you think that is. You say you should have been Head of Household. What are you trying to do? The possible filing status choices are Married Filing Separately, Married Filing Jointly, Single, or Head of Household. ONE of those, not a combination of married and HOH. What does it say on your your Form 1040 for your filing status? It is shown at the top of the form near your name.
**Disclaimer: Every effort has been made to offer the most correct information possible. The poster disclaims any legal responsibility for the accuracy of the information that is contained in this post.**