I slept with two guys within a few days of each other one being on the 31.12 and the other one being on the 2.1 my last period was on the 2.1 which guy is more likely to be the father?

DNA test is the ONLY surefire method for determining paternity, especially when the encounters are so close.

Too close to call. You will have to have a DNA test done after the baby is born.

Impossible to assume. You have to do DNA test