Is the Pain Mngmt office I work for staffing properly?

Hello all! This is my first job working in a private practice M.D. office. My previous jobs included LTC and Rehabilitation Medicare facilities. I work in an office with 7 doctors. I am the only nurse with one additional MA. Other front office employees bring patients back to the rooms however my duties include the following:

Bring all patients back to the room for one of the 7 Dr's., take vitals and history. Clean rooms when done.
I share the following responsibilities with the MA:
Answer all calls from Pt's re: all issues outside appts. including med. change requests, severe pain, lab results. etc. apprx. 150 calls/day.
Listen to and write all Rx requests for monthly prescriptions (controlled substances) minimum of 200 Rx's per day and call pt's when they are ready. Also call in non-controlled rx's to pharmacies.
Fill out all disability paperwork applications
Write LOMN for meds, equipment etc or being off of work.
Pt care for all 7 Dr.'s including injections, caths for drug screens, set up EMG's, dressing changes, Dexascans.
Write and fax/mail all order requests (PT, Home care, etc)
Intercept Drug reps visits, schedule lunches, retrieve signatures from M.D.'s
Assist with PA's for non covered drugs. appx. 5 per day.

I am only asking b/c I am feeling so extremely overwhelmed and want to know if this is how other practices are run and expectations. Thanks