As someone who suffers with Sickle Cell, I try as much as I can to keep hydrated during the day but most especially when I wake up in the morning.
Dehydration can make the blood to sickle because of reduced oxygen level and thereby result in a crisis. You therefore do not want to be without water at any time but most especially, after exertion, in the heat, if you have a fever or when you have an infection.
If you are able to do so, always carry a bottle of water with you, this is probably the advice I can give you. I know that I have had moments over the years, where I have been somewhere without any water and I have exerted myself and it has not gone well afterwards. So, now, I make sure I have a bottle of water around me or some liquid.
I know some people think what is the point of drinking water but but for someone with sickle cell, the point of drinking water is a very important one. You really want to help yourself and carry that bottle of water with you wherever you go.
Have you thought of having a bottle by your bedside, just in case you wake up in the middle of the night, you can take a sip or when you wake up first thing in the morning.
Get drinking, lots of water