switching careers with an engineering background,PLEASE take time to read ,any info is helpful and appreciated?

next year is my final year before earning my bachelors of science degree in mechanical engineering (note not bachelors of engineering degree ,bs. in eng is 3 years as opposed to 5 , and the equivilant of the b.eng degree is a masters of science in engineering ),anyways ,I realized mechanical eng. is definetly not for me a while ago but I decided to suck it up for now and fix it later(my grades paid for it ,my transcript is not pretty ) .I will list some of the careers i'm interested in and if someone can please tell me if it's possible to get into them somehow (graduate school or further studying even another bs IS an option ...but the less schooling i need the better...have enough debt and wasted enough time as is )...the list is

-environmental engineering

-landscape architecture

-Veterinary (yeah i know ...just giving it a shot )

-agricultural engineering

any information you can give me will be very helpfull .....I need to know there is a future in finishing this damn degree