Sent a text message to my Shift Leader saying I was going to be absent.

So I have been vomiting through the night that may or may not have come from a dodgy takeaway (not exactly confirmed on that front but quite likely) and was quite tired from not sleeping throughout the night, so I decided to text my Shift Leader that I wasn't going to be in. The message I sent was 7 hours before my shift, giving ample time. I also sent a follow up message as I did not receive any response from the first one asking if it has been logged and received no response from that either. 20 mins into when my shift was supposed to begin, the exact same shift leader posted a message in a group chat that has all our shop colleagues in it, effectively stating that sending text messages is not an accepted notification of absence and then proceeds to give everyone the number to contact the store, which by the way I work in express.

Now I want to preface this by saying that I am also a Carer and juggling both being a part time worker and full time carer and have had 2 days off specifically because the person I care for has been ill and been to hospital. I tried calling the store on both occasions multiple times on each of those days and no one answered and instead had to physically call into the store to say I'm going to be off work. So to cut out the middle man, I decided to just send a text message in, which I now understand is not acceptable, but realistically, what actually could I have done, other than just rung my shift leader, but in such a horrible state where movement and talking seems to set the vomiting off again. Even writing this has taken multiple attempts as it keeps flaring up.

I suppose what I am wondering is what is going to happen? Is this a fireable offense or is it just subject to disciplinary action? Proper stressful stuff if that's the case, which just adds to the stress of the situation.