It's very easy to underestimate your calories & overestimate calories burned. Instead of white bread with deli chicken, how about some multi-grain instead (or no bread ) & adding some green salad or veggies? I checked out watermelon the other day & it looked awful as it's the wrong season for it here. Enjoy your watermelon! Nice fruit is a bit limited but I can buy frozen berries that are grown locally. Yoghurt with mixed berries is also a great, healthy snack or sweet treat. I add a sprinkle of mixed nuts & seeds on top. You can also do a mason jar with layers of oats, berries & yoghurt that you can take to work as a healthy, easy & inexpensive option. I add a top layer of the mixed nuts & seeds just before I eat it.