People get quite jazzed up the first week on any SSRI--they can feel anxious, restless, agitated. A benzo works wonders for this, and then it's gone by the second week. Perhaps that's what you experience?

Also, some people are slow metabolizers and react strongly to almost all meds. One way of showing a doctor that it's physical and not psychiatric that you have big reactions is to have your P450 enzyme system typed for drug metabolism. It's a routine quest lab now. It's cytochrome P450 2C19 and 2D6 that they run. Maybe more, but those I've found on the quest site. But getting those typed would cover the Prozac, benzos and Cymbalta.

2C19:

Proton Pump Inhibitors:
lansoprazole
omeprazole2
pantoprazole
rabeprazole
E-3810

Anti-epileptics:
diazepam=>Nor
phenytoin(O)
S-mephenytoin1
phenobarbitone

amitriptyline
carisoprodol
citalopram Celexa
chloramphenicol
clomipramine
cyclophosphamide
hexobarbital
imipramine N-DeME
indomethacin
R-mephobarbital
moclobemide
nelfinavir
nilutamide
primidone
progesterone
proguanil
propranolol
teniposide
R-warfarin=>8-

2D6

Beta Blockers:
carvedilol
S-metoprolol
propafenone
timolol

Antidepressants:
amitriptyline
clomipramine
desipramine
imipramine
paroxetine

Antipsychotics:
haloperidol
perphenazine
risperidone=>9OH
thioridazine
zuclopenthixol

alprenolol
amphetamine
aripiprazole
atomoxetine
bufuralol1
chlorpheniramine
chlorpromazine
codeine (=>O-desMe)
debrisoquine2
dexfenfluramine
dextromethorphan1
duloxetine (Cymbalta)
encainide
flecainide
fluoxetine
fluvoxamine
lidocaine
metoclopramide
methoxyamphetamine
mexilletine
minaprine
nebivolol
nortriptyline
ondansetron
oxycodone
perhexiline
phenacetin
phenformin
promethazine
propranolol
sparteine
tamoxifen
tramadol
venlafaxine Effexor