I'm 21 and living at home with my teenage brother and single mom for the next three months. I am paying my own tuition and give my mom $100-300 bucks a month to cover the cell phone and help out. I cook a couple of nights a week and sometimes do laundry and other stuff. Every now and then my mom throws a fit. She cries, points at me, and says I'm not pulling my weight.
My friends say she expects a spouse's share of responsibility rather than a son's share. I can't say anything like that to her without her getting upset. What do I do? Is she expecting too much of me? How do I repair the relationship without overextending myself? How do I survive these next few months?
There is no such thing as a "spouse's share" of responsibility outside of marriage, so put that thought out the window.
Your mother is expecting you to behave like an adult. That she is not expecting an adult's share of the rent (or mortgage), utilities, and other related expenses is all the proof you need to show she's not expecting too much. Even $300 a month is a small fraction of what it costs to support one person, much less three people. I can think of several adults your age and younger who would aspire to the chore list you have (along with the few expenses) because it would be a welcome break. That you can name the chores you have is a good indication of how few you have.
Unless you're doing chores without her having to say a word about what needs to be done, you're not acting like an adult. An adult doesn't have to be told. An adult just does. An adult doesn't list off what they've done because there's too much to list and they have more important things on their mind.
That you cook so infrequently is especially telling. On your own, will you only be eating a couple of nights a week? Who will be cooking and/or providing the other five dinners a week for you once you're on your own? Who will be making seven lunches and seven breakfasts? Since you're not doing the majority of the cooking now — or even half of it, for that matter — what's your issue? If it will be you doing the cooking seven nights a week when you're on your own, there is no reason why you can’t do more now, especially in light of there being someone who is counting on you and who, in large part, supports you.
Once on your own, you'll find laundry will need to be done more than occasionally – what with clothes piling up with greater frequency than this. Doing only my own laundry requires more than an occasional visit to the washer and dryer, so one wonders if you're even doing all of your own laundry – and by "all" I mean the purchase of the detergent and taking the laundry from the laundry basket to the hanger or shelf.
It doesn't sound like you're in any danger of being overextended. It sounds like you have little idea of how overextended your mother is and how you might be able to jiggle that social calendar around a bit to better accommodate her. If you're not willing to forgo some of your social life (you mention friends and having discussed this at some length, so one is assured you're not suffering in this regard) to better accommodate your current living situation, perhaps it is not you who wonders about getting through the next three months, but rather your mother.
You can repair the relationship by giving your mother the respect she deserves by acting as an adult would (read: how you would conduct yourself once on your own) and stop listening to the sage advice of friends who it sounds like have about as much experience with adulthood as you do.
If you can't pull that off for three months, you might want to reconsider the stamina you have for college and/or being on your own. These are both commitments wherein you are expected to be responsible enough to do things without having to be told – and way more than occasionally.