This post ended up being kinda long-- sorry!
I am a PhD student. I took 5 years to get my B.A. and 3 years to get my M.A. I'm one year into the PhD and I have at least another 3-4 years before I'm finished. I became seriously sick during the summer before my 3rd year in undergraduate and was diagnosed within about 6-8 months (I'm one of the lucky ones to get a quick diagnoses). School can be really tough with lupus but as another member said, take full advantage of disabled student services. I've found that in addition to extra time for tests and things like that, these programs can also help you get exceptions to "normative time," i.e., how long it takes to get your degree. Many schools, especially grad programs put a limit on how long you can take. I was surprised by how much disabled students could help me. Depending on your school, you may be able to get priority status for things like campus daycare, which could make life a little easier.
I also TA at the univ., so my "teacher" advice is to make sure your profs and TAs know what is going on with you from the beginning of the course-- and don't assume disabled student services will inform them. I often have students approach me once the world has crashed down around them, for whatever reason, and they would have had a much easier time if they approached me earlier. I should take my own advice though, since I tend to do this too. It can be hard (and exhausting) to tell people about having lupus and what that means.
Another area of study may also help. The sciences (like pharmacology) require a lot of lab time/time away from home. Social sciences and humanities (my area) is much easier to study when you have a chronic illness-- lots of sitting at home reading or writing. But then again, it usually doesn't pay the bills. You've got a lot on your shoulders, having lupus, a baby, and little support network-- you should be proud of yourself for getting any schoolwork done at all! I've been very lucky and privileged to not have to worry about all those extra things.
Best of luck with your studies.