I also smoke 1 cigarette before I go to bed, to help me sleep...
Vodka is your friend! Kidding, kidding! I found that to be the case for me at first. I got some OTC sleep aid, like Tylenol PM, but without the Tylenol. It eventually goes away.
Keeping a clearo loaded with a high nic juice is a good idea too for those moments. I have never subscribed to being obsessed with trying to lower nic levels; nicotine by itself isn't harmful to you. Vape all you want at what level of nic that satisfies you. The goal is to stop smoking, not vape the lowest nic level.
Your body is used to getting a certain amount of nicotine throughout the day. I vaped like a mad man for the first month after I quit smoking at 24 mg/ml, but my one and only goal was to not smoke. I vaped at that level until just recently when I began DIY juice. I am now at 18 mg/ml, but it isn't because I feel like nicotine is bad; it's because I am a cheap ........ Nic liquid is expensive!

Good luck.
Wow, the censor is fast this morning! A cheap son born to parents who weren't married...