Newly qualified and scared :-(

As the title says really... I qualified in September and been in post for roughly six weeks. The ward I'm on is where I was on placement and I really enjoyed it hence applying when I qualified. The ward I'm on is not acute which is one of the reasons I liked it as I never felt on edge that a cardiac arrest might happen as these really scare me to the point where I just freeze. Everyone is being really nice and helpful at the moment but I still feel like I'm not good enough and I feel pretty useless tbh. I'm not signed off on medications yet as my preceptor has worked every opposite shift to me. I sometimes feel that there are gaps to what I should know regarding the running of the ward. I do ask and it has been explained to be but I just forget it. I have already been pulled up on not giving a detailed enough handover and when on nights last week I was on duty with another new nurse (who had been nursing 30 years) who wanted me to do all the medication rounds, I told her I'd not been signed off and she just huffed. I sat in the office doing work on patient care plans while she sat in the day room reading magazines. She didn't want to give handover because I personally felt she couldn't be bothered so I ended up doing all handover for 20 patients whilst don't mind this as it s all experience I feel she took advantage because I was new. I've been told by some colleagues who I should and shouldn't trust and this has also put me on edge as I'm quite a trusting person and I've been told so so will stab you in the back etc etc. I am finding it hard to delegate to nursing assistants and one or two have right out refused to do what I've asked them. I looked on my rota last night and I have been put down as the only qualified on duty one of the busiest days of the week in two weeks. I am really worrying about it. I've had no real support from my preceptor and I have asked to change to someone who took me under their wing but I have also been working opposite to her as well. I feel totally overwhelmed with anything to do with medications, transcribing and ordering etc. please tell me this is normal, whilst I love my job the responsibility and lack of support is scaring me I am seriously thinking about going back to uni to do something different within health.