Best wishes! Glad you're recovering well. Speak to your primary care physician or get a referral to a nephrologist to discuss your situation. Generally, it's not the we become dehydrated more easily, it's that if we do become dehydrated, the demands this places on our single remaining kidney are very worrisome, leading most well informed caregivers to act quickly to reduce these risks. Were you not counselled to be more vigilant about your hydration levels as part of your informed consent process or at discharge from the transplant center?
Regardless, your situation is your own, and now you've experienced a dehydration incident as well, so follow up for improved hydration practices and personal situational awareness techniques. Again, best wishes, and glad you're on the mend. Take good care.