I had sexual intercourse with two different men, five days apart. if i'm pregnant, is there anyway to tell whose baby it is?

No: It can't be determined by timing because the encounters were too close together. Genetic testing would need to be performed after the baby is born to determine paternity.

Probably not: A paternity test will probably need to be done. The possible dates are too close together. Ultrasound, etc is not precise enough. The results should not be considered definitive.

NIPP at 9 wk: There is an expensive but non-invasive form of prenatal testing called by the acronym NIPP(non invasive prenatal paternity) . It requires a sample of mothers blood and some from the designated dad. You can source this on line. The alternatives involving putting a needle up the birth canal or through the abdominal wall to get fetal tissue, or waiting until after the baby is born.