What's Happening W/doxycycline Hyclate I Began Taking Yesterday?

I have begun taking DH for cellulitis. 2 capsules daily.
This is my second day. After eating b'fast at 9 am
today I took the 3rd pill. Almost immediately got very nauseated
and within 5 minutes vomited it up. After a heavy lunch at 1
pm, I attempted to re-swallow the 'spit-up-dissolved capsule
which I had spit into a cup. I've tried taking several sips,
and each time I get nauseated, having hard time keeping down.
So far I have maiintained, but with difficulty. I feel poorly.
Don't know whether to continue taking.

Have looked online to find symptoms for allergy to or
whether there is any food or other prescription that would
interfere. No luck.

My doc is unavailable.

Helpt