Your doctor probably didn't think upping the Prozac dose was a good idea, as you already had insomnia.

Luckily, Prozac is probably the easiest SSRI to withdraw from, as it has a lengthy half-life, but as you're going on an alternate SSRI, you don't have to be completely off Prozac before you start titrating up on the Zoloft. That should prevent you from feeling quite as vulnerable to relapse towards depression during the transition period.

That small dose of doxepin is quite safe, being only about 1/8 of the therapeutic dose. Doxepin and two other tricyclics (trimipramine and amitryptiline) have high sedative potential. The low dose is not a concern for serotonin syndrome.

An alternative to the tricyclic for sedation would be trazodone, but having used both for their actions against insomnia, I personally prefer the tricyclic.

Lar