What are signs of Papillon pregnancy?

We have a 11 month old Papillon that we have every intention of fixing as wel as 10 month old male chiuahuah unfortunately we were waiting until after Christmas for financial reasons. We waited a little too long and she went into heat in February. We did a very good job of keeping her and our male chiuahuah separated. Unfortunately I didn't keep track of the days/weeks she was in heat and at least 2 weeks after may have been 3 my son inadvertently put the chiuahuah with the papillon. I don't know exactly where she was in the cycle. I noticed today and maybe they were like that before but I am paranoid that her breasts seemed larger than I have noticed before, Yikes hopefully I am wrong and she isn't prego.