You could be doing more than just not getting a complete sleep when you don't sleep well. What this article, summarizing findings published in the journal Sleep, says about the effects of sleep interruptions is a good warning for everyone. Not having enough sleep (which varies depending on your specific sleep needs) can cause:
lower levels of serotonin which are associated with anxiety and depression
less body repair while sleeping
increased risk of cancer (due to disruption of melatonin production)
A good sleep is important for all ages, especially children.
The point was made that the five stages of sleep are all very important:
1 - Transitional Stage
2 - Light Sleep Stage
3 - Delta Sleep 1
4 - Delta Sleep 2
5 - REM Sleep
Apparently sleep medicine is becoming a fast growing speciality. We are going to need all these new specialists to deal with the noted 83 (!) sleep disorders that are out there. Very comforting to know about this interest in sleep medicine for those of us with sleep problems.
The article has other information that I did not repeat here but could be of value to you so I strongly encourage you to read it if you have the time.
The bottom line is: If you are having sleep problems - GET HELP!