It might work better if you only try lucid dreaming on nights when you don't have to get up @ 5 am? If there are any nights like that. For me it always works better when I can sleep in as late as I want in the morning, in fact most of my lucids seem to happen after I've had plenty of sleep and sleep late.

Have you tried mantras to remind yourself to wake after each REM period? This worked well for me, especially when I combined it with drinking a big glass of water before bed. You normally wake slightly after each REM period anyway but just barely and briefly, and you just don't remember. So if you engage in a little 'kidney-loading' before sleep, when you do wake you'll stay awake because you feel the need to go to the bathroom.

For my mantra I said "I wake after each dream", because I'm not sure my subconscious would understand a technical terms like REM period.

I had 2 different strategies - for one I wanted to do a full WBTB, so I would go ahead and go to the bathroom, but for the other I wanted to just lie still with eyes closed and remember the dream, so I could fall back asleep immediately for a DEILD attempt. I found I could do this even though I felt like I needed to drain my kidneys pretty badly. I was afraid of a 'bed-wetting incident', but it didn't happen. And I'd also wake after the next REM period (they get longer and closer together later in the night) and I could get up and use the bathroom then if I needed to. Though sometimes I could make it through 2 or 3 awakenings before I purged myself.