Feeling anxious about a repeat blood test and Dr appointment for my 9 year old

[Sanitycheckplease]

Hi all
I just need some level headedness as I am getting myself a bit worried.

My son, 9 had a sickness bug back in the beginning of June. Came out of nowhere but he was really sick but only over a short period, less than 24 hours. He's never had one before and it took him a good few days to get over and get his appetite back as you would expect. He's never really been 100% better. His appetite goes from normal to no existent at times with episodes of lethargy. 3 weeks after the bug he was sick again and was off food for a few days and tired.

I waited to see how it got on thinking it may the heat bothering him but eventfully took him to the GP. She prescribed Gaviscon and said it's most likely gastritis (inflammation following the bug) but also ordered some blood tests. The Gaviscon initially helped a bit but he has since had more loss of appetite and was sick again. He's turning down McDonalds, ice creams...all sorts which is NOT like him at all, so I know something's not right. But I must say in between times he is his normal self.
Last week he had the blood tests and the GP surgery called today saying the Dr wanted to speak with me in a routine telephone call and to repeat the blood test following that. She couldn't tell me why.

I know if it was urgent the Dr would have called directly but I can't help worrying that they have found something. The appointment is not until next week so I know I am going to worry until then. It could be a whole number of things but I know something's not right with him.

What could it be? Has anyone had a similar experience and what was the outcome?
Thanks

It’s usual for a blood test to show elevated numbers when children are fighting something, so I’d assume it’s something along those lines.

I work with kids and one of the kids had these symptoms for months. Constant gastro upset/appetite up and down/fatigue (he was 4.5 and falling asleep during a 3 hour nursery session after a full night sleep!). Mum was told viral, blood levels showed body was fighting something but doctor said it had to run its coarse, but Mum eventually got a referral to a paediatrician who did a stool/breath sample as first port of call. Turns out the wee soul had Helicobacter Pylori for all that time! A week of 4x daily antibiotics has sorted months of discomfort for him and anxiety for mum!

It could be something along those lines, and it the repeat bloods show elevated levels they may move to further investigations.