Is it safe to take one 25mg benadryl (diphenhydramine) capsule solely as a sleep aid? insomnia for a week, taking a toll on my physical and emotional well being.

Yes : One week should be okay. As long as the package inserts are followed. In the long term you'll benefit most from educating yourself about proper sleep hygiene as opposed to a quick fix with pills.

Yes: Yes Benadryl (diphenhydramine) is considered relatively safe although it can cause dry eyes dry mouth and even constipation in some. Some people feel "wired" after Benadryl (diphenhydramine) but if that is not the case for you then you can usually take it safely.

Benadryl (diphenhydramine): On "as needed" basis , and under guidance by your doctor.