Toddler won't eat......help!?

My daughter Vitani is 16 1/2months old. we are vegetarian and i'm confident she is meeting all her nutritional needs. however the last week we have been having difficulty in getting her to eat. she hasn't finished a meal in 3 days and yesterday she only ate 2 mouthfuls of breakfast and refused to eat anything for lunch, i've tried giving her different food, just to get her to eat something, but it doesn't seem to work. My partner doesn't want me to "cater" to her fussy-ness, however the food she is refusing to eat is food she normally loves. Any food i do manage to get into her mouth she spits back out, she is drinking with no problems. i should also mention she is teething, at the moment she has 2 canine teeth and 3 molars coming through, i don't think this is the problem because she hasn't stopped teething over the last 6 weeks, and we have been using bongela about 10minutes before meals. if you have any help or tips for me i'd love to hear them, i have no idea what to do next. should i increase her milk and formula intake while she is refusing to eat? I should also mention that i still feed every night just before bed. thanks bec