what do you do with an undergrad?

i've been thinking a lot lately about the future. i don't really do that very often. i have a hard time with that vision. i don't know what brought upon this whole plan for the future business, but i've definitely woken up.
i've started thinking about the direction i want to take within my biology degree. there are lots of areas to study and i need to pick one. what i've realized from this is that i love genetics and that i've closed off some options due to my just get through right now way of living. due to the fact that my only goal was to pass the class, don't worry about how well you do, just pass it, i only got a D in first year chemistry. the thing is, i really like chemistry and when i put my mind to it, i'm good at it. but i ended up with this D and because of that, i can't take any higher level genetics or biochemistry classes because they all require a minimum of a C in first year chem. blast. and because i'm already so far behind in the whole school thing, and have already spent so much money, i don't want to get into retaking classes.
I am also starting to think about what happens after i get this biology degree. everyone i know with just an undergrad is wandering around wondering what to do with their life. they are either working jobs that have nothing to do with the 4 or 5 years they spent in school, or they are working in entry level lab jobs that they hate, or they are just taking random undergrad classes just to stay in school until they figure out their plan. an undergrad all on its own is useless. i need a plan.
So, due to a bunch of different things that would be a whole post on their own, the lightbulb that came in in my head was med school. i want to be a doctor. and the funny thing is, i have never considered doctor as a career before but i was a lifeguard for 6 years and i loved it. i know they're not even close to being on the same level, but in some ways they are similar. i loved learning about the different injuries and illnesses. and i loved learning how to treat them. as a lifeguard you are helping people in ways that not just anybody can help people. i've always known that i wanted a career where i was doing something usefull. making a difference has always been important to me. people always told me that i would make a good teacher because i've always had jobs educating children in some way. i've taught a lot of kids how to swim and about science and i really like it in those situations, but the thought of actually being a teacher makes me want to tear my hair out. i've had some really great teachers who have inspired me to be a better person. but it definitely takes a special kind of person to be a really great teacher, and i don't think i'm that person. if i'm going to do something, i want to be passionate about it. teaching is not a passion.
i've thought about a lot of different things and nothing really feels like it fits. i know i haven't tried all these things, but thinking about them kinda feels like wearing a shirt that is like, half a size too small. you can put it on, and you could probably pull it off, but its a little bit uncomfortable. right now, when i think about being a doctor, i feel like i've pulled on the right size shirt. it doesn't feel too small and that is the first time in my life that i have felt this way.
this goal is going to kick my ass. i'm nervous because i don't have a great school record. but, if i can ace this year and the next two, i might actually have a shot. thats the greatest thing about it - it's not too late. i've never felt this calm before. i really hope that this feeling lasts.