Have been thinking vs had been thinking [duplicate]

Question

It's a bit confusing due to the nature of thinking.

If I was thinking something and it turned out to be false: I have been thinking that I'm getting sufficient sleep, but it turns out I wasn't. Or should it be had since I just thought that I'm not getting sufficient sleep? I had been thinking that I was getting sufficient sleep, but it turns out I wasn't.

What if I realized a few hours before the conversation that I wasn't getting sufficient sleep?

I feel that "I have been thinking a lot, so my head hurts" is better off with have been.

Also, "I have/had been thinking of calling you" seems to be fine with both.

If we take a different example, I think if you were running for a few hours and are now walking, should you say I have been running..? But if you were doing sprints everyday and decided to jog today, I had been doing sprints... is better?

Answer 1

To pull from another's answer about "have been," "has been" and "had been", https://english.stackexchange.com/a/322822/426160

"Have been [verb] is the present perfect tense and refers to an action that began at some time in the past and is still in progress."

and

"Had been [verb] is the past perfect tense and refers to something that began in the past and was still true at another time that also was in the past."

So, if you were still thinking, or hypothesizing that you weren't getting enough sleep, it would be appropriate to use "have been thinking." But since you said the "thought" (i.e., speculation) that you weren't getting enough sleep was false,, the assumption is that you don't think it anymore, therefore, "have been" would not be accurate.

"Had been thinking" [that you weren't getting enough sleep] would only be appropriate if the realization that you were wrong also occurred in the past and you were talking about that. Ex., I had been thinking I wasn't getting enough sleep until John pointed out that my CPAP had logged use of ​over 10 hours every night last week."

You may want to keep it simple and just use the past tense of thinking and say, "I thought I wasn't getting enough sleep, but I was wrong."