Thank you for the additional information - I hope you’re feeling a bit better this morning - perhaps just from airing your feelings on here?
Without knowing either of you, it’s difficult for me to tell how realistic your fears about your sister are, and how much they are coloured by your own depression. Most people do NOT die of MS. It would be reckless of me to promise it can’t ever happen - after all, there are always exceptions. But it’s not a normal outcome - especially after just four years. It would be very rare indeed.
So I wonder how realistic your assessment of your sister’s prospects is, or whether depression is making you dwell on scenarios that are very, very unlikely?
You should not be missing lectures or work over this. I’m not telling you off - it’s just that you need to strike a balance that doesn’t see your own future jeopardized. How much work or study can you miss, before it starts to have an impact on your prospects? I’m not talking just money, here, but the passport to a career and life of your choice, that you would find personally rewarding. You can’t let that go down the pan! And if your sister is everything you’ve said she is, I’m sure she’d be absolutely gutted if that were to happen, and she thought it was because of her. I think one way to help your sister is to have the best life possible, so that although she won’t be able to do all those things herself, she’ll have the next best thing - she’ll know someone close to her is out there doing them - someone she can be proud of. It certainly won’t be helping her if she feels that she is a burden, and that you have messed up your life for her sake - she would want to know you’re doing well!
An aspect of depression you may not know about is that it can create a strange sort of sense of self-importance, but in a negative way, i. e. believing you are in some way responsible for everything, but ONLY the bad stuff! You are NOT responsible for not being able to do the impossible (make your sister better), and your sister is NOT reliant wholly on you, so that every time you work or study, you’re somehow letting her down. Her situation is much better than I originally envisaged, with a doctor actually in the family, and she’s seeing an MS nurse, so she’s not struggling along with nothing, and totally dependent on you - she has other lines of support. Is there a husband/partner around too, or is she a single mum?
I hope the work counselling service is of some help. They must be quite a sizeable/reputable employer to offer that. Perhaps the counsellor can help you strike the right balance, of being a support to your sister, whilst not sacrificing your own ambitions. You cannot put the rest of your life on hold, and spend it within a five-mile radius of her, in case anything “truly bad” happens. If you want to travel one day, you need to be able to do that with a clear conscience. It isn’t wrong. It’s unrealistic for a young person to have to spend their whole life just a phone-call away, in case anything happens. As we grow older, we all have to face that something might happen to someone while we’re not there. If it’s not sick sisters, it’s ageing parents. It’s a fact of life you can’t always be there for everybody, all the time, “just in case” - nobody can! And normally, our relatives wouldn’t want it. My dad would have been horrified if I’d quit my job or sold my house to be with him in his final months (he lived 100 miles away). He’d have been totally against anything so drastic! I did, of course, spend what time I could with him at weekends and holidays, and the medical staff were very good about letting me know when to expect the worst, so that I could be there in time - they have experience of these things!
But all this may be totally irrelevant. MS reduces life expectancy only very slightly - most people will have a normal or near-normal lifespan. In general, it is quality, not quantity, that’s worst affected. Not that that’s very good news either, but it may help keep things in perspective for you.