6 month old not sleeping through the night??

Di

Help!! My daughter used to sleep all night I’m talking 9-9 kinda thing and as soon as the 4 month regression hit she slowly started to have shorter and shorter stretches. She never really went back to full nights she had a random full night a couple weeks back but that’s it. Is anyone else’s 6 month old not sleeping through the night? And for those with babies that do what sort of routine or what not do you have?? She never had to be rocked to sleep and now she wakes up as soon as I put her down! Need help or ideas please! Being a mom of a toddler as well, I’m extremely tired! Lol thanks