Hi, I have had the same thing with my 5 year old daughter. It seemed to be a phase and eventually she just stopped it.
It's so hard and emotional to deal with and very difficult to keep patience with it.
When my daughter did this to me and I would just constantly repeat to her 'no, we don't hit' and explain why. I never did it back to her and never raised my voice. It just eventually stops. Thing is, they're not doing it to hurt you, it's most likely because of something on their mind that they dont know how to explain or how to feel about it so it's an emotional outlet.
It could be something as simple as worrying about going back to school.
I also repetitively said to her things such as 'if you want to talk to me about something that's fine, when you're ready, but we must not hit'. Its surprising that even though you probably feel like screaming yourself, one of the best things to calm the situation is to just keep saying 'I love you, I'm here for you, i understand that you feel angry but let's think of another way to make you feel that way'. Its important though when they're finished that you sit and talk to her and ask if there is anything on her mind that she may be worried about and explain why hitting is not acceptable. Then provide the consequence and say because you hit there will be no ipad today or whatever.
With the tidying etc, it's sometimes triggered because they are at a stage of feeling independent so dont want to be told what to do. So maybe try something different than saying 'can you tidy up please' such as 'what do you think to this idea - if we tidy up now we can then play...' So they feel like they're involved rather than being told.
You've done well to last 3 weeks before asking if it is normal! Youre doing great, just stay calm and she'll copy you. Always end it with a big hug.