still worried

Still a worried momma! over the last couple weeks I've realized that Logan's oxygen level has actually been lower than I thought. He looks great- is still active- still playing and actually doesn't look that blue to me. However on the playground at school Logan's o2 was between 69 and 74. If he goes below 75, he is suppose to have oxygen, but there is not an order for o2 at school because in the past he would only drop that low if he was sick, then he was home or in the hospital. My first call was to the cardiologist when I realized that he couldn't stay above 70 playing on the playground and not above 75 just picking up toys- he quickly recovers with rest. His cardiologist feels like it is a pulmonology issue. So, after not being able to get into the pulmonologist, I requested a x-ray from the pediatrition and the x-ray was negative for pneumonia- Logan's usual cause for low O2 with a pulmonary cause. So, I decided we would wait a week and 1/2 for the pulmonology appt. Well, Logan ended up in the hospital Saturday morning. He had a 103 temperature and the er doc thought he had a aspiration pneumonia- Noone else really agreed, but the dose of iv antibiotics made my little guy feel better. Logan's pulmonologist came in, he doesn't think that the low O2's has to do with pulmonology. So, we see him in the office on Thursday and he says Logan looks and sounds great. Ummm, what about the low O2 with movement? I put a call into the nurse of the cardiologist again. I am having a really hard time being patient. I'm having a really hard time not worrying way too much. Not sure what options are out there to treat a 3 year old with tricuspid atresia and portal vein thrombosis???? I keep wondering if I am overreacting? If I should just enjoy the time we have here with Logan.