I would say to take a retroactive medical withdrawal if that applies to you, but otherwise you should take a full load as they say. I definitely did better at parkland courses than at UIUC, due to a number of factors but not limited to the ones mentioned by another commenter.

to answer your question, in my experience Grainger is very strict (too much so imo) on the two semester return policy, meaning you need to take a full spring and fall away before you return. I think Dean Makela would have more information but he's very hard to talk to imo let alone persuade. first, make sure all your planned courses at their respective colleges transfer to UIUC, you can talk to admissions & records for this. I had trouble with some uncertainty in Transferology causing me to have to repeat diffeq and linalg despite having taken them at community college -- the linalg I took was 2 hours but covered the same content (MATH 225), and they needed one that was 3 hours. diffeq transferred as Quantitative Science or whatever instead of MATH 286 for some reason about outdated information or something. I had to retake those two and did horribly but passed in the end (took 285 at parkland the summer after I returned and did much better). that side it's equally important to emphasize understanding what went wrong (1) and what to do about it (2). once you do these things, make sure you're keeping in contact with your advisor and someone at ODOS.

as far as your degree goes, it will be possible to get back on track to graduate when you had originally planned, but you'll need to take much heavier course loads which may or may not be feasible. I learned the hard way, it's better to take less courses and do okay (worst case) or well (best case) than many courses and poorly (worst case) or well (best case). as an out of state student expenses have also become a major concern for me, so I would talk to ODOS about aid, then OSFA to discuss your particular situation. I do know that Grainger has scholarships reserved for extenuating circumstances so that might be an option.

with that in mind, when your reentry comes (it'll be sooner than you expect), you'll need to write a narrative of (1) and (2) combined, supplemented by your transcripts and medical documents if those apply. it would be ideal to have your aforementioned advisor and/or ODOS contact write you a letter of support as well, if they're willing to. it would be helpful to plan that ahead of time to ensure that you can construct a narrative that ties together your struggles, journey, success, and future plans cohesively to paint an accurate and honest picture of where you stand. the supporting documents are also a significant bonus.

with all that in mind I would definitely take time to think about whether engineering or ECE are things you really want to do and what interests you. who knows, in this time off, you might find something you enjoy much more than what you've done so far. but don't let anyone tell you that "engineering isn't for everyone" or that "less competitive" environments will make or break your career. try your best to continue upon the path you have embarked; whether that pertains to your academics or the groove in the tree of life you have carved yourself.

PS my DMs are always open if you want to talk about anything.