I took what I think is the equivalent to 100mg of benadryl (diphenhydramine) 10 hours ago. I got really tired and woozy for a couple hours. Feel fine now. Any concerns?

No. The effects of the Benadryl (diphenhydramine) have likely worn off and there is no need for concern. Not sure why you would need to take 100mg of Benadryl (diphenhydramine), this is way higher then the daily recommended dose. Please consult your doctor if you have questions about dosing or if the symptoms you are treating are not well controlled.
No. This is what one would expect from taking Benadryl (diphenhydramine) especially at the relatively high dose you had taken. Most people start with 25 mg and work it up from there. There are several other non-sedating antihistamines available and you should consider trying one of these instead if drowsiness is the issue.