Is this "ever" grammatical here?

Question

1: I walked up and asked, “What is the matter?” and I regret ever doing that.¹
2: You can see by the situation I'm in that I regret ever using drugs.²

Is this ever grammatical here?

OxfordDictionaries includes the definitions at any time and at all times; always. In the cited usages, does it mean "I [now] regret having done [the regretted thing] at any time in the past"? That seems unlikely in the context of #1, since the action could obviously only have happened at one specific time.

Or does it mean "I always regret / have always regretted doing it"? In which case, is the regret implied to have started immediately after I did it? That seems unlikely in the context of #2, since presumably the speaker repeatedly used drugs after the first time.

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_{1. That a Man Can Stand: The Evolution of a Nation}

_{2. Google}

Answer 1

It is very correct and quite common. I think the best way to explain it is to paraphrase its meaning:

It implies (in your example at least):

"[I regret] that it even occurred to me to do such a thing"

or more dramatically

"I rue the moment I decided to do such a thing (in the first place)"

or in a roundabout way:

"I wish I'd never done such-and-such"

Answer 2

The 'ever' in your examples is grammatical. It's used to make an expression more emphatic.