Any tips on how to stay the course?

The main tip I have is to remember your "why." Why do you want to become an environmental engineer? I get anxious about starting a research project that I do not think I have the expertise for or taking another course. But when I remember my "why" I feel much more motivated and less anxious. For example, I am currently doing a PhD in Environmental Engineering because I want to improve people's health and the environment in a sustainable way. My goal is to be able to bridge the gap of technical experts and policy makers who do not always speak the same language. I also like having the technical expertise about why things happen.

As for classes, it's important to remember that EVERYONE struggles at times during their engineering classes. I realized that professors and TAs love to help students who come to office hours and that homework assignments are much less daunting (and take much less time) when you work with classmates. Going to office hours and making friends with grad students and professors is also a great way to find mentors! One of my first mentors in engineering school was a professor who was excited to do research with first year students.

Also remember that you are coming in with so many skills and much more experience than your classmates will have. Engineers have to write reports and communicate, which are skills that take time to build. If you've already studies some environmental policy, have good communication skills and attention to detail, that'll take you a long way!