@Cuzo
First things first breh water drink more of it
a damn gallon a day.
Second take your folic acid/hydroxyurea(if applicable) every damn day
I also take fish oil and L Arginine because it helps circulation might be broscience but it can't hurt.
As far as cardio you can do it but you have to take baby steps and know your body, you know when you are overdoing it and feel like something might be coming on if so down two gatorades immediately and call it a day workout wise. I went from not doing cardio at all to walking >jogging > running> jump rope sets and I can even do light sparring for a couple of rounds but the important thing is to know your limits.
I don't know hemoglobin variation you have but if it's SS/SC you are going to go through crisis, it is what it is. Don't let this discourage you take the appropriate time to heal up/take your meds and once you feel able again do work.
If you have any questions I'm here breh, shoot me a pm or @me.