I had been mentally preparing myself to go two months without a proper gym while studying abroad in London. I was 200% sure I was going to gain at least 5-10 solid pounds while eating, drinking my face off, and not working out as rigorously as I had been while in the States. I was okay with that.
Sometimes a hectic schedule makes one never want to leave the house after a long day of classes, work, or chores. However, if you just include exercise in your daily routine, it will give you the energy you need to keep going with your lifestyle.