Waiting to start my new meds!

If i could remember all the preventative medications i had taken as a child to try and cope with the sever migraines that i had the list would be LONG!!! So on reflection its might be a good idea that i can't remember them all cause it may well scare me.
Now as an adult, my migraines are back as i have already said on this blog, the first of the new round of preventative drugs that i have tried were beta blockers, they worked for a while, a couple of months if i am honest and then they just stopped working, so my doctor put me onto another medication called Pizotifen, again this worked for some time longer than the beta blockers, all said and done i lasted around 5 or 6 months but then once again the effect that they first had just seemed to fade.
So right now i am gradually coming off the Pizotifen, all in all it should take around a week, then i start on the next medication which is Gabapentin, its a strong drug and the starting dose for me is 100mg a day, with a review with my doctor after a couple of weeks to see how things are going.
I'm not really sure what to expect apart form feeling tired which seems to be first side effect that is stated, i have to say after reading around the first 5 side effects i stopped. If i carried on reading i am not sure i would start taking them.
Lets just see what happens, i should be starting them in a few days, so cross everything that they work!