It may take 2-3 months to feel back to normal; that is, once the levels are optimized. 100mcg may be enough but it varies from person to person, so you will need to have TSH tested 6 weeks after being on the dose and then adjust as necessary. It will be critical to make sure that you are not without thyroid meds in the future.
What was the reason for the TT?
When was the last time your blood was re checked? Seeing as you do not have a thyroid you will be at the mercy of the medication dosage. Your blood should had been check 6 weeks after he put you on 200 mcg for 7 days and then 100 mcg after that. I hate to say this, but it will take a while to get your dosage level to where you will feel your best.
I had my TT taken out almost 15 yrs ago; I was on 200mcg for 12 yrs no problems, than out of the blue the last 3 yrs my levels have been dropping to where I was hyper. Changed dosage, okay for a yr. then hyper again, then hypo, then hyper, now hypo. I am either over medicated or under medicated. Just two weeks ago my level was 5.90, so we upped the dosage again.
The key is to always get your levels checked once a year, and six weeks after any dosage change. You want your level near 1.0 since you do not have a TT, but everyone is different in the TSH level.
You can try B12 to see if that will help with the energy level. How is all your other blood work? Potassium, Calcium, Vit D?