I'm so sorry to hear you've been through all of this the pain & stress of it on its own is bad enough without losing your job on top of it. Some people can be so cold when it comes to understanding what others are going through- especially employers. Unfortunately as you said, because they gave you 1 months notice & you'd only been there since September, you were still within your 6 month probation they obviously knew that they could get away with it too.
When I was 17 I had a job in a shop & there were many times (at least 2 days a week) when I had a call from my boss, asking me if I could go in & cover someones shift (which I always managed to do despite being in college 3 & a half days a week & having lots of other things to deal with!!!) About 4 months after I started I was hospitalised with meningitis (thankfully they caught it early but I was still very poorly) my mum phoned my boss telling him the situation & that I wouldnt be able to work until I was better.
The day I was released from hospital he phoned me asking if I could go in the next day to cover an 8 hour shift??!!! When I told him no, that I was still quite ill & it would probably be quite some time yet, he began telling me that it was best if he let me go as he needed someone who he could rely on & basically accused me of "leaving him in the lurch". Because I had no official contract & was still on probation there was nothing I could do. It really annoyed me because I'd just had a huge scare & he does that to me, despite all of the times I'd covered other peoples shifts.
Don't let this beat you hun, your health is the most important thing in this situation. Hopefully you will have some answers when you get the laparoscopy over with (that waiting period before the lap is a pretty tense time as I know you just want answers & Its the pain & not knowing that makes it worse). Use that time to just have a bit of "you time" & take some time for yourself.
As for the income side- have you looked into things such as DLA or PIP & income support? You sound as if you may be elegible for something & it might be worth looking on here: entitledto.co.uk/benefits-c...
I hope everything works out for you- & that all goes well with the laparoscopy.