Lately, I’m having VERY long REM cycles. I’m talking about 4-5 hours…I’m not kidding…is this normal? Can anyone tell the reason?
Sorry, but I think this is very unlikely.
How do you measure the time? Do your dreams just feel like they last that long?
How do you know that you are in REM at all? You can also be dreaming outside the REM periods.
If you are really convinced that you got REMs that long I’d visit a sleeping lab, they’d probably be interested 
tapir
I can understand your concerns…but I woke up at 7am and went back to sleep right away…I entered my dream and did not stop dreaming until I woke up 3 hours later…I know I could have been fooled by my subconsciousnoss but I can tell if there are “breaks” in my dreams…there was a continious story I followed…I’ve dreamt at least 3 hours nonstop but i’ve dreamt before 7am…so it’s more than 3 hours…
This is so weird because my dreams are not always that long…I’ve heard that the worldrecord REM sleep ist 3:58 hours our something… 
btw, it seems that this board has grown a bit…hehe…missed you all 
You cant really say how long your REM is without EEG.Time is funny thing when you sleep.
Anyways…even if- just be happy for what you have:)
If you still worry about it,just find centres when they have EEG and go under check.I personally wouldnt though.
take care