Maria, is your gum sugarless? Even if it is, it is full of artificial sweetners which have high fructose content or otherwise bad for you. Small quantities of aspartame or stevia should be ok, but even they can hurt because they cause glacimic changes and insulin spikes. So if you find you’re not making enough progress, try to find different gum or skip the gum for a week and see what happens. If your progress is fine, then stick to natural sweetners as the evidence is mounting against a lot of the artificial sweetners, like Splenda.
As far as changes to the program, I found doing 5x5 deadlifts to be excessive in the novice version (completely drained me) and ramp-up 1x5 DLs worked better (a la Rippetoe/SS). If you still need more DL volume for whatever reason, I've lately tacked on 5x10 on the last day after the other exercises with 30-50% 1RM weight (a la Wendler/531's Boring But Big). Also needed to add extra arm work. Calves were a lagging issue for me BUT the sheer amount of squats made them come up naturally. Otherwise, this is perfect. Stick to this protocol with adequate rest, good form and a slight caloric surplus and you'll be somewhere strong in no time.