Kind of odd to buy dog food only to have to doctor it up with something else to get the dog to eat it. Real food doesn't need to be doctored up.
Ok, back to the real issue. Put your dog in a crate while you all eat. Then clean the table and high chair, take the tray off the high chair after you wash it. Fix your dog some real food and let her eat next. You have that little dog a nervous wreck. Also you need to have her spayed. It sounds as though this heat cycle is really hard on her. What ever you do, don't let her out of the house by herself. A male dog can climb any fence when a female is in heat, and could kill her if it's a large dog. Use the pampers or even doggie diapers, but take it off to let her potty, but please go out with her!!! I can't stress that enough. If you don't want to keep her, then call the Yorkie rescue.