Im worried

I'm 21 + weeks and still not eating how I'm supposed to I'm just not hungry I can go days with out eating but I stay hydrated should I be worried.....my son is in the 20 percentile he's supposed to be in the 50 they say that I don't need to worry about that I feel like such a bad mom 😞 I just want to force myself to eat but I can't I just can't any advice ladies or someone who knows what I'm going through help me