Sleep training 5 months old

Hi all,

I would really appreciate any advice on how to make my 5 and 1/2 month old DD sleep longer at night.

We have a good bedtime routine. Wind down, bath or shower, pj, feed and sleep at 20:15 latest. I breastfeed and I put my daughter in her cot right after breastfeeding. Sometimes she falls asleep right away, sometimes she takes up to half hour. But the important thing is that she is capable to fall asleep on her own. However during night once awake she won’t go back to sleep on her own. She needs to be breastfeed. I decided not to breastfeed every 2 hours ( won’t sleep past 2 hours) and I give her dummy instead. Sometimes it works sometimes not. I do not mind to wake up and breastfeed her. I do mind waking up every 2 hours or less. I’m tired and it started to get on my nerves. I have a short temper with my hubby lately and he does not deserve it.

Anyone has a success story and can advice me what to do to make her sleep longer at night?

Thank you