Workings so hard right now!

So i just got a job as a housekeeper and i also just found out I'm 5 weeks pregnant. Well when i found out i was pregnant i was even more excited to start my new job. Well i didn't realize how hard it would be. I'm so tired and it really hurts my back. Plus when I'm a couple hours in i start to get horrible cramps. I sweat all day and i just feel like I'm pushing myself. They told me not to do that when i exersize so it worry's me. I know if i wasn't pregnant this job would be a piece of cake! Could this job hurt my pregnancy in any way? Or am i just being a big baby?