No offense but it’s very unlikely your 24 hours of fasting are the reason for any of your issues.
What do you eat and drink when you are not fasting?
If you believe you might have heart issues or diabetes, you shouldn’t be asking reddit but actually contacting your doctor right away and getting some tests done.
I will just say that I easily hold on to water when I eat carbs/sugars of any kind ( including fruits, wholegrains ) and don’t drink enough. It takes me about 4 days of dry fast for my legs to deflate for example. It is a night and day difference.I know it’s totally food related though.
But again, 24h doesn’t do much, neither harm or good for most people. It has already been discussed often. In this case the refeed would be more interesting to hear about.