NC for this and will try and set everything out as I hate a drip feed.
DS2 is 4 months old and has already been admitted twice to hospital with infections. First time he had a kidney infection and a cannula with antibiotics. We were in overnight and then at the hospital for appointments every day for 3 days. DS was really poorly in the run up to being taken to A&E. I stupidly arsed about dealing with 111 and the GP like you are supposed to do. He typically had temperature spikes when we weren't at appointments, 🤦🏼♀️as is the way of the baby. He responded well and had a kidney ultrasound after which was totally normal. I was told this was rare and we were just horribly unlucky.
When DS1 was born he picked up an infection during birth, got jaundice was dehydrated and we were readmitted for a week. He was cannulated five fucking times. The cannula was out more than it was ruddy in. I was there for a lot of the attempts and frankly found it horrific. When they said DS2 needed one I burst into tears and told them about DS1. The doctor said having both your newborns cannulated with different infections is vanishingly rare, she said it was like winning a crap lottery.
We've just gotten back from DS2's second hospital stay. Went in with a suspected UTI but it turns out his main illness was a viral respiratory infection. Basically he had a bad cold. A fucking cold. We were in hospital for 4 days. A&E was BUSY when we arrived and we were straight through. We stayed in the acute care room on the ward most of that time. There were consultants being paged for my baby. His heart rate was over 200 for 2 days and his temperature was 40 and would not come down. They strongly suspected meningitis or sepsis. He was desperately unwell. I was absolutely terrified. 
My question I suppose is where the hell do we go from here? He had a cold for Christ's sake! I know it's a nasty one at the moment but it was still a cold. He was surrounded by children that had major surgery, chronic conditions and for a while he was sicker than all of them. I just think it's not normal to have a hospital admission every 2 months. But how do I get him tested when he is medically fine? What would anyone test for?!
I also don't know how the hell I parent normally now. How do I take him to baby groups or happily send DS1 to preschool knowing they could pick up colds there? I am so paranoid about his health it's insane. I just looked up his weight and noticed he's dropped 2 percentiles. I hadn't been worried about it before because everyone comments that he's big.
All I do is feed him! But now my mind is going to dark places, why is he lighter than he should be? Why does he keep getting infections? I can't turn it off. I don't know if it's all too raw and I need to give it time. I keep thinking of the reasons why the other lovely children were in hospital and thinking he has the same. 
The problem was compounded by DS2 being EBF so I've done all the admissions and stays alone. DH was allowed to drop stuff off and relieve me for a few minutes but that was it. I found it so hard. I felt so alone and mentally I'm in tatters if I'm honest. I flit between thinking this is a normal reaction to an absolutely shit situation and total blind panic about DS2. I don't know where to turn with it all and I'm hoping someone can offer some pointers to help or maybe calm me down at least.
Thanks for reading my ramble too. 