Baby won’t sleep unless in my arms!

My little girl is 3 weeks Monday and she literally won’t sleep in the afternoon and all evening unless I’m holding her and I’m falling asleep with her in bed and I want her in her bassinet! We have a queen bed and co sleep with my 2 1/2 year old son and he kicks her and rolls on her if I’m not awake to stop it! I can’t get her to stay in bassinet the minute I put her down she screams!! she slept great for a week in there and now won’t sleep but a few hours and than just wants to be with me! I’m going crazy she’s awake from 5pm-9pm and she’s exhausted but still wakes up! U also can’t put her down when she’s awake for more than 5 minutes I don’t know what changed! Any suggestions on what to try! I use swaddles for bedtime!