I can't get back to sleep after waking up? but I need to WBTB

I have issues, once I get a certain amount of sleep, and wake up (mostly if I physically get up) I have a hard time getting back to sleep. This morning after 10 hours of sleep (bad idea I know) I tried to WBTB.
I watched a subliminal video, drank some apple juice and I was SO confident I'd have a lucid dream....if I could get to sleep.
I know I'm supposed to set the alarm to 4-6 hours after sleep, but I didn't.
I only got 3 hours of sleep the previous night, so I went to bed around 10 last night, woke up at 8 and tried this. I tried to WILD, then I gave up. I eventually started getting weird imagery as I was trying to get to sleep (you know when you start dozing off and your mind shoots in every direction) and I did that and fell asleep a lot but after 10mins I would always wake myself up because I would be breathing weird....I can't really explain it but I like jerked the breath out of me and it would always wake me up.
So how can I get to sleep for a WBTB (DO NOT say to set the alarm earlier, ASIDE from that!!!) thanks :)
sorry, I didn't know what section to put this under

What do you do when you get up? I can wake up at any time, and, if I need to be somewhere, I'm wide awake. Otherwise, I can get right back to sleep

I get that way too. I just won't be able to go back to sleep. I'd assume your body says, "I've had enough sleep. Time to get up"

Yeah, you've slept enough.

Also, what's your problem with alarms? They are the most wonderful things ever.