Teen pregnancy and work

Hello everyone. I need a little advice. I am 18 and pregnant and still in school but, I only have three days left. I'm also six months pregnant. I have a job as a waitress and I've had it since I was sixteen but now that I'm pregnant and it's extremely hot and humid I'm dreading going to work. I go to school from 7:00-3:00, then drive to work and start at 3:30-9:00 sometimes later. Waitressing is pretty hard. I have to deal with people on top of getting an endless list of full ups done and sweep and mop all the rooms. I feel like I can't handle it anymore honestly. My feet swell (we can't sit. I don't work a 6 hour shift so I'm not required breaks plus I'm the only one working so I wouldn't be able to break) and I get dizzy and just extremely sore all over. Also the skin around my vagina and thighs are literally burning/ chaffing cause the walking and sweat. I don't want to quit because I need money but I don't feel good doing this anymore. It makes me miserable. I'm having a hard enough time with school and I feel so discouraged. I feel slow and shitty when it comes to my job. I just feel like my body isn't handling it. Even my brain. Plus they just asked me to work 6 days a week once I'm done school. I have bad asthma and I get heatstroke really easily. I'm so worried I just want to keep my baby and I safe. I know this is all over the place and may sound like ranting so I'm sorry. I really need advice tho if anyone's willing to give some? Oh btw I work 1-9 and 11-9 once I'm done school.