Hi there
Not been on this forum for ages, but DS2 (14 months) is just starting to become quite fussy (although we've not ever conquered the veggie thing on there own yet?!). Just had to reply to your post, as DS1 who is nearly 4 also eats NO veggies, and only banana and apple (under duress!), so you really are not alone!
DS1 has such a "phobia" of veggies, that until very recently would not even entertain the idea of trying a tiny bite of a vegetable. I say recently, as he now earns "reward" stars for trying new things, and it is having a better effect than anything we have ever tried before. However, he still gags on even the tiniest taster of a vegetable, so I feel terrible even asking him to try! He has always been a very fussy eater even from day 1, and there were many times I literally thought he would die if he did not eat better!
HOWEVER, at nearly 4 he is a happy and healthy little boy would seems to be developing/growing just fine! I now think the human body is very clever at adapting, and I am a little less worried than I used to be!
For your own peace of mind, perhaps you could give a viamin suppliment to him (there are several flavoured liquid ones on the market for toddlers). Also, have you tired the drinking fruit pouches? If your LO likes the drinking yogurts, the fruit versions may be a hit too?!
Another thought - does your LO have daycare with other children??? i think the peer pressure thing is very important to them, and from what nursery say, DS1 has always eaten far better there than at home! (although still no veggies!!)
Good Luck - I know exactly how you feel!