6 week old rarely sleeps and always has to be held in order to

I’m a ftm and I seriously have no clue what to do about the fact that my baby insists on being held constantly… she fusses in arms until she falls asleep most of the time.If she’s awake and we put her down she cries either within seconds or within five minutes. If she falls asleep in my arms and I try to put her down in the bassinet or somewhere else, she wakes up within 10 minutes except at night..that seems to be the only time she will sleep in her bassinet. We’re going to meet the woman that will be watching her tomorrow since I return to work on the 20th and I know she isn’t going to be able to constantly hold her.. she watches 3-4 others (ages 2-4). With how much she cries and wants held I feel like the sitter isn’t going to be able to handle her with the other kids..I’m terrified she will get short fused. I keep envisioning my baby just laying in a bassinet crying and crying or someone hurting her because she won’t stop crying. The only way we can get her to sleep is by rocking her and keeping her in arms. She hates the swing and bouncer for some reason. She only slept around 4 hours total from 6am-10pm yesterday and we don’t understand why she isn’t sleeping more. She never has.. I only get about 3 hours of sleep a night. I never get to nap through the day because she doesn’t sleep long enough. We’ve always been told that newborns sleep 16-20 hours a day and that’s never been the case.. I wish lol she gets so overtired sometimes that she gets over tired and then struggles the relax to fall asleep. I’ve tried so many things to help her but nothing seems to help. She does have reflux and is currently taking Zantac to help as well as eating Similac alimentum formula, 3oz every 3-4hrs. We give her gas drops or gripe water as needed and even occasionally use the Mommy’s bliss nighttime gripe water to help her sleep but I’m not sure if it really does help with sleep honestly. Has anyone had any experience with any of what I’ve talked about? Tips for getting her to be ok with being put down for awhile or fall sleep on her own? She’s only 6 weeks tomorrow and have been told you can’t spoil them with snuggles this young but I really don’t know. I’m new to all of this. She’s our rainbow baby and we tried for years to have her. I love her so much and just want her to be happy and settled. I feel like I’m the one doing something wrong and worry about her going to a sitter. The woman she is going to is very experienced and highly recommended but I still worry.