I feel your pain - I have the reverse problem in that LHT gives me insomnia (and made me add bodyfat, tho also muscle), I tried adding carbs, and working out earlier in the day but nothing helped. Recently I've completely quit lifting workouts and just did for HIIT and this has finally worked - I've been having my best sleep in several years these last few weeks. That said, I accidentally IF'd yesterday (no time for more than a few bites) and did my HIIT - insomnia last night. It seems IF gives some people insomnia so if you're IF'ing you might try stopping.
Me: 41, 5'11", primal since Dec 2011, 73kg, 15%BF but looking to drop to 10%ish
Exercise: barbell 1-2 times a weeksprints/metcon 1-2 times a week, surfiing 1-4 times a week (workouts get dropped for surfing!), movement through the week
Food: primal but a little higher carb than most - white rice, bananas, sweet potato, also a bit of dairy.
Sleep: has been problematic but recently good - currently taking melatonin and 5-HTP