I
vape almost continuously, and could easily go through a 5ml bottle in 2 to 3 days, particularly when I first quit analogs. The thing to do is find some flavors you like with your preferred throat hit and vapor and get the 30ml bottles. Remind yourself that
vaping can be somewhat expensive at first but is ultimately significantly less expensive than cigarettes, both in store cost and permanent damage to your body (hence huge medical bills in the future). Further remind yourself that you're almost certainly healing your lungs and body by avoiding the analogs, so go ahead and vape away!
P.S. Trouble sleeping can be any number of things and there's not enough info. Nicotine is a stimulant, so if you're having trouble sleeping, try cutting out the nicotine at least an hour before bed, cut out caffeine 4 hours before, no exercise 4 hours before but some exercise every day, and try to go to bed and wake up at the same time daily - helps regulate your circadian rhythm.