hey, gum contains ALOT of carbs if you chew through 3packs no matter if its sugar free or not... i try to chew less than 5-6 pieces a day. i get this bad breath when i wake up too!
but i think there is a way to counter the bad breath: you just need to eat alkaline foods like broccoli! to neutralize the acidic values! I read that on gameover from cutdiet!
for me it took a 8-9 days to enter the deepest stage of ketosis. my ketotest were reporting 150++mg/dL ketogens in my piss. it was really really dark dark purple! i have around 20% bodyfat so i only do carb up every two weeks... gonna see how it works out next week (no carb up this weekend).
and to OP:
you need FIRST to get your body to adapt to ketosis. this will take anywhere form 7-12days or more. at this time its best you didnt eat any carbs at all. maybe 5g max. after that adapation period you can begin to add carbs into your food.
from what i read from dr mauro pasqual, if you do well on the diet, you should be in the ketosis all the time. you should still be burning fat while filling up your glycogen storage. then it should only take around 8hours or something after you've finished your carb up before you see positive again on the ketotest. so say you begin carb up on friday evening and quit on saturday evening, then when you wake up on sunday and do a ketotest it should report a few ketogens in your piss... i did carb up on saturday and ended it on sunday afternoon, on monday afternoon i was back in ketosis, so from personal experience i works. it doesnt need to take several days to enter ketosis again!
edit: oh btw, because of your high bodyfat you should either do carb up once every two weeks, or if you wanna carb up every week, then the carb up should consist of ONE MEAL only. and that one meal would be in macro 60c/30p/10f. aaaaand your diet calories should be your lean body mass in lbs times 18 minus 1000kcal. so you should eat only 2700kcal or something right now. you can raise this when your bodyfat gets lower (and you get more lean body mass). i do a 2200kcal diet at a weight of 190lbs. and i lose 1-2lbs a week.
and xtend is doesnt have any carbs or anything except maybe sweetners which i dont know much about, so drink it like crazy. unless you buy the grapefruit/melon xtend, which i remember seeing had around 10g carbs per 100g or something.