Border Tollie is now 22 weeks and has been teething for the past 8. His appetite has never been as expected, but now he's barely eating anything unless he's hand fed. He vomited last night, bringing up kibble and this morning bringing up saliva. He hasn't eaten anything since 9 o'clock last night. In the past two days he's lost 2 large teeth and I'm wondering if it's related.?