Morning Sickness Nightmare

I have been SO sick with this pregnancy basically from week 8 to now week 16. Most days I either eat nothing at all or what I do eat I vomit back up. The most concerning thing for me is that I’m not able to even swallow medications on some days and that includes my prenatal vitamins. I have been put on Zofran or Phenergran and sometimes those don’t even help… the phenergan helps more but gives me terrible headaches and dizzy spells. Should I be concerned about not being able to take my prenatal?