Ask your doctor about diclegis. It's another medicine for the morning sickness like Zofran is but doesn't make you constipated. It's working pretty well for me. Good luck!
I caught Gastro at the end of my holiday in Spain, I had sickness and the runs and became severely dehydrated and ended up in hospital because I couldn't even keep water down - I think I was 13 weeks at the time. Baby will be fine as long as you are staying hydrated. I would contact your GP to find out if you can take the mess that you are on because I know that even many herbal remedies are frowned upon by the medical world.
It's not a nice feeling, and I sympathise with you greatly. You could try Dioralyte to rehydrate you and replace any of the nutrients that you may have lost through sickness or the runs.
It does get easier. Hope you feel better soon.
I had this issue in early pregnancy nothing you can really do, but stay hydrated it will stop.