Yep. DS1 (then 14 months old) was grisly, off his food, and a bit lethargic so took him to GP, he seemed fine when we got there but she did all the relevant checks for the symptoms we listed and we were told that he was probably coming down with a virus. DM is also a GP, and checked him over that evening. He seemed a bit under the weather but nothing drastic.
2 days later we took DS1 to A&E. He'd been breathing really fast and seemed a bit (strong emphasis on bit) lethargic. Perked right up as soon as we got there, he was sitting on my lap, clapping his hands, laughing, playing row row your boat.
Five minutes later we were swarmed with doctors, and we found out shortly after he was in heart failure. A special cardiac team from the nearest (2 hours away) Children’s heart unit collected us and blue lighted us to the nearest children's intensive care.
They did all the tests at 3am, he was diagnosed with two heart defects, TAPVC (pulmonary veins connected to superior vena cava instead of the left atrium) and a VSD (hole in heart). We were transferred again at 2pm, this time to the hospital with the heart unit, and he was in open heart surgery by 7pm.
We found out later that it was the ironically VSD that had kept him alive and asymptomaric all that time, as babies with TAPVC normally turn blue at birth or shortly after.
Two weeks after surgery, we all went home, and all is well 4 years on 😊 he's still very dramatic.
(NC as many people who know me, know about DS, and don't want my other posts to be public knowledge)