てっきり...と思う => surely; certainly; without a doubt N3
と思う => I think N5
ようと思う/ようと思っている => thinking of doing; planning to ~ N3
~が故 => therefore; consequently​; because of; due to ~ N1
Cause, reason
あまりに(も)~と / あんまりに(も)~と => too much; so much… that; excessively ~ N3
Extreme level
かと思ったら/かと思うと => just when; no sooner than ~ N2
あまりに (も) => too much; so much… N3
Extreme level
~とおもう(~と思う)      => tend to, be about to… N4
Intent
にあたり/にあたって => at the time; on the occasion of ~ N2
に...がV-てあります => Object status N4
Description
あまり(に) => too much; so much… that; excessively ~ N2
... にと思って => To do..., to let... N2
Purpose, target