Asha is Off Colour Again

Last night Asha had her supper at 9pm, as she always does, but by bed time she was off colour and refused her bed time goodies. If Asha refuses anything edible then immediately the alarm bells start ringing. Her temperature was 39.4  and she was quite flat.  Unable to sleep for the thoughts I heard the first wimper at around 12.20am ... but I was too late and the old lady hadn't been able to hang on to the explosion of diarrhea. I stayed up for a while and then went back to bed, she was let out again twice over night, but to be fair I'm not sure she needed to go.
This morning her temperature is down to 38.8 and she's quite sprightly. There has been no diarrhea since about 1am and she's just been trying to go through the recycling!!!! As you know she's quite an old lady and this is the third time this has happened since last Summer. I just looked back through my blog for reference,  exactly the same symptoms in July and September - but nothing since. I know she was treated with antibiotics and right or wrong I had some spare so gave her one last night and one in a bit of white fish just now. I will let the vet know but since she has improved dramatically since last night I will now monitor the situation.