Ok my dad's blood type is supposedly o- and my mom's b+. is it possible for me to be bloodtype o-?

Genetics: Since your dad is o-, the only blood type he can give you is o-. Your mom, being b+, can still pass on to you an o- blood type depending on the blood types of her parents. Here is a pretty good tutorial on the genetics of ABO and rh blood types. http://www.biology.arizona.edu/human_bio/problem_sets/blood_types/intro.html.

Yes: Yes, it is possible for you to be o-.