Would it make you feel better to hear that I yelled at my nearly-4yo dd and sent her to bed without dinner for biting her 6yo brother hard enough to leave a bright purple bruise? (disclaimer - she fell asleep for about an hour then came down and had dinner)
I lost it with her because the 7month old ds has been grumpy all day with teething; 8yo ds has been in trouble at school for retaliating against another boy who punched him; 6yo ds is the most forgetful child you ever met (not his fault, currently being assessed for ASD). None of these things were her fault, but when she hurt ds2, I didn't respond rationally and constructively. I called her a horrible little monster and told her to go away.
My point is that everyone loses it from time to time. What differentiates between those who are bad parents and those who are frazzled good parents, is the ability to recognise that you've acted in a way you're not proud of and wish that you had handled it differently. The fact that you're posting here for advice shows that you are in the latter group.
Firstly, go and bring the presents inside. I promise you will feel ten times worse if they are rained on or stolen.
Then have a cup of tea.
If the kids are still up, use Bogeyface's excellent line: "I am sorry that I over reacted but your behaviour was disgraceful and I am very very disappointed with you. We will discuss this tomorrow but right now you are to go to bed with no messing about".
Then have another cup of tea (probably decaf this time).
Tomorrow, talk to them. Explain to them that their behaviour is upsetting you and that you want to have a lovely, calm house where everyone pitches in. You are a team, especially when their Dad is away and it takes everyone working together to keep the house neat and tidy and everybody happy. The kids are old enough to understand that (it's the sort of approach that gets through to my lot) and talking to them like mini adults may be more effective than taking the authoritarian role at them.