Every time I started a SSRI (including genetic Zoloft) my doctor would prescribe me zanax (actually alprazolam .5mg.) It's written to take line tablet twice daily as needed. My doctor is the best, admitting to me he took something similar to Zoloft, and whenever he started a new med he would take zanax to ease him into it. Worked pretty good for me, it's not perfect,but i would take halves like you mentioned to not exceed the dosage. I can't say my attacks where ever quite as strong as you describe, but when i would start having heart race, or feeling of panic i would take it immediately. After a while i got to know when i would have triggers and i would take it before hand to prevent anxiety/panic. He write me 60, and i still have too many too count. Don't worry about getting hooked, if you don't constantly exceed you should be fine. Also, don't fear your doctor, if they are a good doc they will understand what you a re going through, if you have to stand up to them demand better care. They are there to care for you. When i was 18 i tired to get help from another doctor,i told him iw depressed with anxiety and he laughed at me and said i was too young to be depressed... Wrong!! I felt dedicated and even though i never went back to him, i went 7 more years without seeking help,fearing they would till mine I'm to young. Don't let them tell you how you should be, if you need help them demand it,or find another doctor!
Now i only take zanax as needed which i would say is a few times a month and only halves,depending on what social gathering stresses me. As for caffeine, i still drink soda and i love my coffee,and energy drinks but sometimes they make me feel jittery. So take caffeine in smaller doses and slowly work your way back up to what you are used to taking. Keep record of what you take and what you are doing prior to any attacks and soon you'll conquer this!