Six Month Sleep Problems

I've been told a lot recently that I should have kiddo sleep alone and cry it out.

There is nothing I hate more than when someone tells me what will work best for kiddo's sleep. I say this because from the time he was a newborn he slept better with us. Not only did he sleep better, but so did we.

Now things are changing, but not how you might think.

He's clingier than ever. He used to let other people, however short a list, put him to bed. Now he wails unless he's snuggled and nursing. Sleeping alone? Forget it. Cry it out? Don't be ridiculous. He's been crying quite enough.

In the middle of the night he's begun crying and thrashing in his sleep - at least 3 times every night if not more. He's also going to sleep later and waking up earlier. He's so tired these days he's got bags under his eyes. It's awful.
I'm forcing him to take at least 3 naps during the day which helps his overall mood, but he's still spacey and fussier than I'd like. And of course with the sleep I've been getting, I'm crankier too.

So what's causing all this sleep disruption?

There are several reasons I've discovered as possibly ruining our nights:

1. Allergies - possible. Baby noses get stuffed and it gets uncomfortable causing them to fuss in the middle of the night. I have allergies which means kiddo could too, so it isn't off the table. Still he's not really showing signs of allergies.
2. Illness - while I understand how this could be (see the allergy reasoning above), I don't think this is the cause...unless junk in the air counts as illness? Right now there's a lot of crap in the air around here - pollen, fertilizer, cut grass, and just dirt. There's only been a little rain and the junk in the air is getting to everyone.
3. Night terrors - caused by over-tiredness. Possible. Night terrors are nightmares that babies and young children don't wake from. They thrash around and cry horribly until the terror is over. Soothing a child in a night terror is supposed to make them last longer, except when I soothe kiddo the episodes end sooner so I don't think this is the cause.
4. Developmental leap - possible. Kiddo is *really* close to crawling. I mean, really. He loves tummy time and gets super frustrated when he doesn't get to move around. I guess you could say he's commando crab crawling at the moment (going backwards on his belly) but he's got the urge to do the typical crawl. Apparently when the leap is achieved, the night crying disappears.
5. And then there is teething. Kiddo does have two teeth coming through the bottom gums right now, so it could be discomfort from this as well. It's hard to know. Christian doesn't think it's worth giving him Ibuprofen for anything at this point so soothing will have to do...
6. It could also be a combination of things, which is just as likely as some of the individual reasons.

Whatever the case, I'm being religious about kiddo's napping. It seems to help, but he still has these bags under his eyes. I guess I'll just have to wait until whatever this is passes for those to disappear. In the mean time, we'll nap and soothe and sleep how we sleep best.