Hey Susan, I was in your same shoes...2.5mg trying to move to 5mg which was very hard.
My doc took me from 2.5mg to 10mg (where I am now) as he said 10mg is the lowest therapeutic dose. It was very counterintuitive in my mind and I was scared to jump up by a factor of 4. However, the additional dose didn't make me feel any worse (then when I was trying 5mg) and in fact I started feeling better quite quickly.
Might want to talk to your doc about
it as I've read 10mg is really the lowest therapeutic dosage.
Hang in there!