Can't get into courses needed for my plans

So I'm in a Biol Major and have some required 2nd year courses for that, but I also need to take Chem 112. I couldn't enroll until today because of the reserves but now all of the options that worked with my schedule are gone. There are no labs that don't conflict with my required Biology classes, and I cant change sections for those classes since they're all full now.

Do I contact someone about this? Should I just hope someone drops the sections I need for chemistry?