LMA,
If anything Benadryl can have a calming/sedative effect! In fact some people use it 'off label' for anxiety/sleep.
It is very gentle, but some find it makes them too drowsy...so you'll have to see if a full or half dose, and at what time is appropriate for you.
This is one that really has little worries attached to it...as it is given to children...and has virtually no s/e's besides some sleepiness.
I am sure that you will find it is an easy and beneficial med for your needs.
S.C.