I'm having doubts about whether it's worth spending another 4-6 years getting a PhD... it's a long time to be trapped in university, and I've heard bad things about it.
So in 5 years, no idea. Either a job somewhere, or a PhD.
In 10 years, even less of an idea.
I am thinking the same in a sense. Probably unlike you, my issue is whether I have what it takes to do a PhD and whether I would love to do high level research in Mathematics. I can say to everyone now that I love math and I wish to be a lecturer/professor one day but the math I have done so far is nothing compared to what I will be doing next year, so I really don't know at this stage whether a career in academics is for me. I simply don't hold enough knowledge in the field of mathematics to be able to say I 100% want/will do a PhD, but I do know that mathematics will feature heavily in my career, whatever it may be.
Recently I have been re-assessing my career path/goals and I think maybe after doing a bachelor's with honours I could work as an analyst say for the government or do a Master's by coursework first. This would be an interesting career, applying mathematics to real-world situations and working within a team that can have many specialists such as physicist, astrophysicist, statistician, biologist, other mathematicians, etc. There would still be plenty of time to do a PhD and have a long career in academics this way, but you get more life experience and diversity.
This might not even happen, I might go straight on to a PhD after my honours and start a career in academics. Only time will enable me to see where my passion truly lies after I actually have some experience with high level mathematics.
If it takes you 6 years to do your PhD then you're doing it wrong. Much shorter than that if you have a decent program and you like your chosen topic.
Anyway, in 5 years I'll probably be finishing up PG med but after that I'm completely undecided on where I want to go.
4-6 years might be referring to a PhD in the US and that is if you love your chosen topic. The average for completion of a PhD in the US is 7 years with 57% of students who begin a Ph.D. program in the US will complete their degree within 10 years, 30% will drop out or be dismissed, and 13% of students will continue on past 10 years.
For Australia, the average is more like 4.5 years.
If I end up doing a PhD I would love to do it in the US. The reason for the long length of PhD's in the US is because for the first 1-2 years there is a coursework requirement and an entry exam after the coursework so you can start work on your dissertation. The coursework is usually masters level where you can be awarded a master's degree along the way to your PhD. Australia's PhD's have no coursework requirement.