How do I approach this? Any suggestions (from anyone)? Do I contact the pharmacist or do I contact my doctor?

Here is what the doctor from webmd had to say when I asked him about it a while ago:

Dear Sarah,
In order to start clozapine, patients have to get formally registered by their doctors in the Clozapine Risk Evaluation and Mitigation Strategy (REMS) program (see https://www.clozapinerems.com/CpmgClozapineUI/home.u). A specific pharmacy needs to then be designated by your doctor that will receive from him the weekly white blood cell tests (actually, what's called the absolute neurotrophil count, or ANC) in order for them to be able to dispense clozapine 7 days at a time. Clozapine is usually started at 12.5 or 25 mg/day and then increased every 1-2 days by 25 mg to a target range of about 300-450 mg/day, per the manufacturer (see Clozapine - FDA prescribing information, side effects and uses). 100 mg is rather a high starting dose.and one would need to be extra cautious about dizziness when standing (called orthostatic hypotension) and sedation.
Dr. G.

Here is a little further in the discussion:

Me: Well, I do feel better about all of this. He is on the registry already and advised me that the pharmacy will fill the prescription once I have filled the blood work and signed the paperwork. He is going to start me on 50 MG which is, according to him, admittedly high. He says my body requires higher doses of medications and he feels confident that this will not over medicate me. We are going to move up 50MG every 3 days until we hit the (hopeful) target of 300MG. Does this sound reasonable to you as well? Thanks again.

Dr G: Dear Sarah, Yes, reasonable. Watch for sedation and orthostatic hypotension when standing. Dr G