It is totally ok if your son does not want to eat food right now. He will not starve himself, no matter how many days it seems it has been since he has eaten more than 2 bites of anything for any meal. He is still happy, energetic and naughty. He is fine.
His refusal to eat is not a direct reflection of you as a mother not offering foods he might like nor is it for lack of trying to present a variety of foods for him to sample. Don't take his disinterest in food so personal. You are just fine, too.
However, you need to get over it and stop getting so frustrated about it. Stop doubting yourself and stop letting others comments chip away at your confidence. Have more patience with your son right now because it may be like this for some time, like, maybe until he is 8.
You can do it, and you will.