During the week, i only seem to sleep in two 3-4 hour segments. fall asleep around 11 pm, wake up at 3am, fall asleep at 3:30 to wake up at 6:30. then i sleep from 7-9. is that harmful?

Many people have sleep difficulties, for a multitude of reasons. Some doctors feel a total of 8 hrs nightly is ideal and you total in that range. If you are experiencing daytime sleepiness, or "brain fog", you might consider an overnight sleep study to evaluate problems, such as sleep apnea.

I agree a sleep study to rule out sleep apnea is needed. Not sleeping from sleep apnea can be harmful. Not getting sufficient sleep can affect mood, memory, and cause high blood pressure and weight gain, car accidents(if you drive) , and a lack of concentration

Some sources say sleeping six hours a night is good, followed by a two hour siesta around three p.m. I think the latin countries may have a jump on the rest of the world, because they have been doing this for as long as I can remember. They compensate by staying open for business until late in the evening, but have long, free times mid-day It's a lifestyle, but OK for this pattern of sleep.