[adjective] + 得 + 很 / 不得了 / 要命 / 不行
[psych verb] + 得 + 很 / 不得了 / 要命 / 不行
[verb] + [object] + [verb] + 得 + 要命 / 不得了
These are degree complements – words after 得 that say how far an adjective or feeling goes. 得 follows the adjective or verb, and the intensifier closes the phrase. They are spoken and informal.
得很 is "very" with more weight than 很 in front. 不得了 "beyond measure" is stronger, and goes with good or bad. 要命 "enough to kill you" and 不行 "unbearable" are the strongest, and lean towards discomfort: 累, 疼, 饿, 热, 冷, 难受.
要命 also works with a feeling you like, for humour: 喜欢得要命 "crazy about".
A verb with an object repeats the verb before 得, as with any degree complement.
The degree is already in the complement, so 很 or 非常 doesn't go in front as well.
The object can't go after the complement.
These don't take 不: there is no negative form. Use 不太 or 一点儿也不 instead. For the everyday degree complement – 跑得很快, 说得很好 – see 得.