Farm job during pregnancy. Your thoughts?

Chelsea
Hey, y'all! I'm a 23 year old FTM due May 4th. 
I work on a horse farm 5 days a week as my form of work because it is flexible and it works well with my schedule as a college student. I have been working there, doing the same thing for the past year and a half. I clean stalls (take a wheelbarrow of waste out, then put a wheelbarrow of sand back in) and feed horses every day. I occasionally move some bales of hay a few feet so that I can cut them open and feed the horses. Therefore it is pretty labor intensive.
My midwife said this its fine as long as I was this active before and it wasn't a new activity, but I want to know your opinions. I make sure to stay hydrated and I take regular breaks, but what did your OBs and midwives say about exercise and activity? I don't want to harm the baby.