I feel like I can't do this

I thought I could do 2 jobs at once but the schedules aren't going as smoothly as I thought they would. The new job I want to make a priority but at the same time I need to give my current job a better notice and have a schedule ready for them to work with. I REALLY love working at the library but I might have to quit and I really don't want to but I'm already so tired and stressed. I feel like my director at my current job is frustrated with me and my mom keeps telling me I'm going to fuck up an opportunity and it just sucks.