Some of this is not a training problem, and treating it like one wastes time your dog may not have. If they are distressed when you leave, if they growl or guard their food, their toys or you, if they are frightened on the lead, or if anything about them changes suddenly at any age, contact your vet the same day. A tip from a website, ours included, is not the answer. If it cannot wait, contact your nearest emergency vet now.
With a Labradoodle, watch their weight, their stomach and the way they move. If a puppy has vomiting or loose faeces for more than a day, contact your vet rather than changing their food at home. A young dog who sits down on walks, or a limp that comes and goes, can be their hips, elbows or knees. If their back legs go wobbly in an excited game, stop the game and contact your vet. A dog who slows down and gains weight on the same food may have an underactive thyroid, and pacing at night in an older dog can be the start of Cognitive Dysfunction (dementia in older pets). Bloat (GDV, a twisted stomach) is most common in large, deep-chested dogs, so skip walks and hard play shortly before and after meals. A swollen, tight belly, retching with nothing coming up, sudden restlessness or drooling is an emergency: contact your vet now.
They'll be at the bowl at five. If five o'clock comes and they aren't, tell your vet.