In the wait of NPs answer. Lack of sleep is terrible.
Borax have a short half life in the body, hair tests are frequently wrong. Boron doesnt accumulate in the tissue as eg. fluoride do. Hair tests can show like a high calcium, but it can actually be a deficiency due to utilization problems. They can show low fluoride, as the overload is in your pineal gland or bones.
Stop the boron for 2-3 weeks just to assure yourself that this it isnt the problem. Aluminium is a good antidote (like clays)
Then to the real problem; overdosing vit B; I cant sleep after dosages as you mentioned. My heart race, thought race, I am afraid etc. Stop it!
I can only take low dosage of vit B, but only after a 2 years brake due to this insomnia, high pulse, heart thing similar to yours.