I found that I would get very irritable and 'nervous' feelings when I first switched. I actually still get it on occasion when I vape too much or use too high a nicotine level in my liquids - I recommend dropping down the nicotine content. When I vape 24 mg I get irritable and tense, when I drop to 12 mg I do not.
I've had this experience too. I've only been at it for about a week but I since I can vape in the house I'm doing it way more often than I was smoking. My first few juices are all 24mg or 18mg, so I bought some VG and have been cutting them down to half or so. Now I can vape at will without getting too tweaked out on the nicotine.
I thought I would need high levels (was a filterless RYO smoker) but I'm finding that it's not the nicotine that is making me vape so much, right now I just need the hand-to-mouth thing nonstop.
No idea if that's what is happening to the OP but that's what I am dealing with.