Ill baby that is overtired

[JaffaSnaffle]

My DD2, (1.0) has had 2 viruses recently, the first ended up in quite a serious chest infection, very high temp and course of antibiotics. She has just got over that, and seems to have caught another virus. It is wreaking havoc with her sleep, and I am struggling to work out the best way to help her.

She has never been the best sleeper. I fed her to sleep until 2 months ago, when I did some gentle sleep training with her, (never left to cry, laid her down when she was standing in cot, shush-patted if very unsettled). This stopped her night wakings, and she started sleeping through the night, although she tended to sleep 7.30-5.30 and then refuse to go back to sleep. This was definitely the high point in her sleep patterns.

Her naps are erratic, and I know that this is part of her problem. She either has 2x45 min naps, or 1 longer afternoon nap, but she varies in what she needs, and it is also impacted by my taking DD1 to playschool in the car, (20 min drive that can send her off to sleep at the wrong time). I think back to how regimented DD1's routine was, and I feel sad that DD2 does not have the same.

Anyway, the upshot of the illnesses is that she is overtired, and incredibly hard to settle to sleep when she wakes. She has had diahorrea with the antibiotics in the night, which has reinforced wakings. She screams and cries, and won't be consoled, unless she is breastfed. If she goes to sleep when breastfed, it is now impossible to transfer her to the cot, without waking, and crying. She is breaking my heart with crying. Until she got ill, she was on 3 bf a day, and I was hoping to cut back to 2. Now she is feeding quite a lot again. I am hoping to wean her back again once she is better.

How can you help settle an overtired poorly baby please?