I accidentally got rid of Pheobe and she was my only uchi villager. Is there any way for me to get another Pheobe? If not I guess I have to find another uchi villager.
you have to have at least 16 more villager move out before your town is eligible to have a lost villager move back in. they call this "cycling" through villagers when somebody is just getting more moveouts at fastest pace possible so they can reach point of looking for their lost villager (usually buying him/her from a forum like this one). if you do a search you can find guides on how to "cycle" villagers.
Like they said, sixteen villagers need to move out before you can get a Phoebe back. Once you hit 12 outta 16, the villager will start appearing on Main Street. It takes forever, but if it's a villager you really love, then it's worth it.
I'm currently going through the same thing to get my Lolly to move back.
Good luck getting your or another Phoebe back! ^_^