No OB until 28 weeks.

Hey mums. I'm 20 weeks pregnant with twins. I don't have an obstetrician and the one that my family doctor has referred me to won't see me until at least 28 weeks. I'm growing really concerned, my dr doesn't seem to have a lot of knowledge regarding twin pregnancy and I have a lot of questions. Have any other mums had to wait this long to see an OB? Is this normal? Thanks a lot!