Deciding that one more hour of sleep may harm?

I wonder if my reasoning is sound:

I decided to get up at 5am because I would need to get up at 6am at the latest, and now I am fairly awake and non-groggy. I remember a few days ago having a really tough tired day, and based on how disoriented and groggy I was upon wake up I believe I had woken up in deep sleep or something. I need to be alert for a morning meeting.

On the other hand I am still not over the flu, lingering tiredness and congestion and such. So usually I would have said "the more sleep the better", but now that I am more aware of sleep cycles I am beginning to question that.

Is it better to get one more hour of sleep and risk waking up in the wrong time of the sleep cycle but possibly get some more restorative rest, or is it better when waking up an hour before one's absolutely-must-get-out-of bed time to not bother going back to sleep because it is not enough time to do one much good?

Upon rereading that question it is phrased in a way that is too influenced by my current bias, so if you could please rephrase it in your mind to be a more "objective" question, and answer that based on your knowledge and opinion, I would like to hear what others think of this.

Regardless of sleep cycles or whatever, I strongly suggest you get more restorative rest - I mean, it's all well and nice waking up at the right time in order to get to a meeting, but you're not going to pay attention during the meeting if you're groggy and tired from lack of sleep, right?

Can I ask: what time do you normally go to sleep and what time do you normally wake?

I normally go to sleep sometime between 9pm and midnight, recently more often closer to 9-10pm because I have not been feeling well and been exhausted, and I cannot go to bed earlier because I get out of work in time to pick up the kids by 6pm, then we need to eat/do homework/relax a bit/bathtime/reading books -- all within 3 hours. Then I have to get out of bed no later than 6am. So if I go to bed at same time as my kids with no adult free time, that means 9hours of sleep tops, and I need 6hours of sleep minimum to function. 6am is the latest I can get up and still get kids ready for school and get myself to work on time.

The point I was making here is that a few days ago, I did fall back to sleep after a 5am wakup and then I woke up at wrong time in sleep cycle, and I was groggy and tired all day. Today I woke up at 5am knowing that I could at most sleep for another hour, and decided that was not worth the risk of what happened a few days ago, and I do feel ok not groggy today.

I see...well I'm inclined to believe it would be better just to get up and start your day if you woke up an hour (or whatever) earlier than you normally do, as going back to sleep does make things worse - judging from what your wrote, and from my own strange sleeping cycles, we can both agree to that due to our own experiences.