Before you get all stressed out about your choice to join IB, I just want you to take into consideration that sometimes, IB students tend to overexaggerate things A LOT. For some of us, It can be a coping mechanism. Like @ashields20 said if you're a workaholic, you should fit in nicely into the program because you'll never be bored. On that note, Ib better prepares you for university, With the program, you'll get a feel of how university life will be like because there is always plenty of work to be done and teachers won't move around tests all the time for just your convenience (at least they never did for me). Plus, colleges/universities like to see that you went the extra mile and that you challenged yourself. Even if you don't graduate with an IB diploma (hopefully, you do!), they will at least recognize that extra motivation that is required for the program.
As for CAS, as @ashields20 said, you may volunteer at similar places to the hospital. However, the important thing in these circumstances is that if you are interested in doing this, you may want to volunteer for an established company or organization that relies on its volunteers and would consequently reprimand you if need be. That way, you have the added motivation coming from the fear of consequences. Another possibility is that you found a club at school taht revolves around something you are passionate about. For me, that was an ecology club where we basically tend to plants and trees, pick up litter and attend protests in favour of climate change. Hope this was helpful :)