After donating my kidney will I be able to still eat, drink, and take herbal supplements like I used to?

Yes. You should be able to do anything that you could previously. However, you will want to have regular checkups with your doctor to follow your kidney function.
One kidney. Maybe taking less will do.You are going to need to be extra careful with your remaining kidney. You should research everything you take some herbal supplements are removed by the kidneys.You will also need to let your doctor know every time you are going to be prescribed anything.Such as antibiotics, decongestants (including over the counter) you instantly will have less than 50% kidney function.