If you wanna do physio then a physio degree maybe? I know it's pretty competitive but you finish your sports science degree, while getting physio experience and then apply to do physio after you've finished?
Don't do nursing for the money. Its long hours, relatively low paid for what you do and its a very difficult job. Bank nursing is probably a good idea if you want to get some experience of what nursing entails. I don't know anything about sports science but if you're enjoying the course and you're doing well in it, maybe you should consider finishing your degree and then doing something else.