From a nurse prospective

Hi I currently work as an RN at one of my local hospital. I'm hired as a Postpartum/Pediatric nurse but I float a lot to Med/Surg as well. I'm getting stressed out on my job because there's a lot of days where I don't get a break not even to use the bathroom. The problem is that my supervisor/chief nursing officer view my area as one of less acuity so therefore they will staff it with 1RN and 1 LPN with 15 patients. However, they never take into consideration all the respiratory distress pediatric patient we get and even though these women may just had a baby some have other illness that must be address in the postpartum stage as well. We also get a lot of surgery patients not just c-sections but total abdominal hysterectomy, hernia repair,robotic hysterectomies basically any woman with abdominal surgeries. The LPN that works with me is not IV certified and she doesn't like doing work in general. Give her one task and she spends all day completing it because she wants to take a break continuously. I'm like over my head with this one and I'm be a sick nurse because I'm not eating or just stopping for 3 minutes of me time. The last day I worked we started out with 4 patients which is fine but then I started getting new admits back to back and some at the same time. Our hospital has implemented a bucket load of paper work just for one admit so it takes twice the amount of time or more to admit one patient. The LPN let's call her Sally did only vitals never tried to help with the paperwork that was listed as LPN/RN to complete. I had to call all the consultations, start all the IVs and meds. It's only this LPN that don't want to work but all others I have work with r fantastic. However, everyone in the hospital refuses to work with her so I get stuck with her all the time. I don't know if it's the lack of teamwork or the lack of staffing but its taking a big toll on me and my body. I know my post is long but what I need to know is from a nurse prospective what should I do?