Missed period, elevated esr and crp. what could be cause?

Various causes: You could have an infection, or you could be pregnant. Do you have any other symptoms of infection? Would suggest starting with a home pregnancy test and then get a checkup from your physician.

Many things: This problem can only be solved by seeing your doctor and being evaluated face-to-face. After a thorough examination, your doctor should be able to tell you what's wrong and what to do about it.