ok easy enough, what you need to do is firstly look at your bodys compisition! fat % in relation to lean body mass % ( muscle, bone, organs)
if you have a low body fat % this is usually around 12 % or below then a higher calorie diet is needed along with a revised eating plan. this would usually mean you are to eat 3 meals a day standard! and smaller portions between them, cutting out the crap & not over loading on any set types of food ie bread, potatoes, meats etc etc. think ouside the box - smoothies, soups, nuts, seeds pulses!! I know its not easy to eat often but it is a must!! work is no excuse, dont pass the blame to your employer they want you in good shape, if your not fit & heathy would your employer still want you working there!?? didnt think so, so your health comes first in my book!
next after looking at your diet you need to look at working out, you dont need a gym or facilities... body weight exercises can be performed easily enough... its important that to understand that these 2 things go hand in hand exercise & diet! you need to look at both....
if you want further advise use the lil PM button LOL
hope this helps