I don't know, I think caffeine can effect people differently, like there are some people more sensitive to caffeine than others, some people may not have as high sensitivity.
I've never had caffeine jitters, only when I was about 12 or 13 and started drinking coffee going onto larger amounts, after that, I think one's body gets slightly immuned to it, at least I seemed to over years, now reaching 50, I've noticed it can keep me awake and restless in bed if I drink coffee late in the afternoon or evening.
I never had that, only now in the past couple of years.
Maybe your body doesn't have much tolerance to it, and I wouldn't say "yes" or "no" as to if this is causing extra problems. It is a stimulant, so if a person is sensitive to caffeine, I can see it winding someone up.
(((((( candy )))))))) I'm sending you many heartfelt wishes for luck,patience,healing and innerpeace with this all.
Past few months I've been so lethargic, docs and pdocs feel it's mostly due to the Hashimoto's and the thyroid nodules, already developed 2 new ones and I'll be seen again by endocrinologist soon, another ultrasound and then needle aspiration of the nodules to rule out any cancer.
But this physical stuff can mimic or contribute to depression.
Sorry for my latest soapbox rantings on thyroid disease, but because it is so common, it may be worth having a physical and/or bloodwork just to rule out if this can be part of what you are experiencing. Hyperthyroidism can mimic bipolar hypomania to full mania. Hypothyroidism can mimic bipolar and uni-polar depression(s).
Please take care now, and let us know how things go.

DE