weaning off Dilantin and on to Keppra

I am currently being weaned off of Dilantin and on to Keppra XR.  I have been taking 200mg to 300mg of Dilantin daily for over 20 years and my seizures have always been well controlled and I have had limited side effects.  My neurologist recently suggested I switch to a newer drug as she said long term use of Dilantin can cause bone loss and liver damage.  I was in my final week of weaning off of Dilantin and taking a 100mg Dilantin every other day and two 500mg Keppra XR daily.  I began having terrible problems with numbness and tingling in my fingers and hands.  My job is very detail oriented and I type a lot so this has become a huge problem for me.  I have also had trouble with severe drowsiness which usually leads to irritability.  I finally called my neurologist yesterday as I was having physical difficulty with typing and functioning at work and was finding myself very emotional.  She suggested Dilantin withdrawl may have been causing the problem with my hands and I am now going back to two 100mg Dilantin a day with an eventual 6 week weaning while staying on the full dose of two 500mg Keppra XR daily.  I took two Dilantin yesterday and I do feel like my hands feel better today.  I am also experiencing a heightened sense of smell which I have never experienced before.  It isn't a constant issue, but I do find myself overwhelmed with smells several times a day.  This is a new thing so I am thinking it must be the Keppra.  It is really troubling to me.  I actually took a "mental health" day today from work because I just needed some personal time to deal with my frustrations.  I am feeling very tired, sleepy and upset that I am having such difficulty with small everyday tasks.  No one else really understands what it is like to feel this way.  Has anyone else experienced these symptoms? Please tell me they will go away.