Help! Toddler won't sleep.

So Dylan is 18 months now (where did the time go?!?) and the past WEEK we've been having nap/bedtime problems.  It started last Monday where he wouldn't go down for the babysitter and has continued since then with Tuesday being the only day he didn't fight his nap or bedtime.  He had a slight clear runny nose and some loose stools so I thought maybe his 2 year molars were coming in (he has all of his other teeth).

We went out of town this weekend and it continued still.  He just won't be put down.  How do you put down your 18 month old for naps/bedtime?  We are still reading/rocking and milk sippy.  I was putting him down awake and he'd just roll over and go to sleep by himself.  Now he's falling asleep in our arms and the moment he realizes you're putting him down, he flips out.  I've even had to resort to him sleeping in bed with me because that's the only way he'll go to sleep.  I do not want that to become a habit but I thought since he was "sick" or "teething" that he could use the extra comfort.  I do not want to be kicked and head butted all night, not to mention I fear he'll fall out of bed or open our door and fall down the stairs.  When we finally do get him down in the crib (usually at the hands of my husband-he seems to be better at it) he has been waking up in the middle of the night crying.  If he does STTN he's waking up an hour earlier than normal.

Right this very moment we are crying it out and my nerves are shot.  Naptime/bedtime has become so stressful I dread it!!  We went to one nap a month or so ago as well. We have our 18 month pedi appointment on Wednesday and I hope he can provide some insight as to what's going on.  I'm starting to get worried.  Where did my good little boy go??  I hope there's nothing wrong.