The ground will thaw within some days, and in a couple of weeks (i.e. May) you should be able to retake the offensive.
What do you plan to do? An attack in the north, to help out your Finnish allies? A strong offensive in the center, aimed at conquering the Soviet capital, Moscow, and hopefully at destroying a big amount of Soviet armies defending it? Or, seeing that your fuel stocks are slowly running out, a more economically based offensive, a drive for Russian oil aimed at Baku - and Stalingrad...?