"It's important to be realistic with your expectations for yourself and your family - take a couple of days to land," he suggests.
"We've seen from previous lockdowns that anxiety peaks going into lockdown and coming out of it. So settle in, get oriented, and if you're an employer, go easy on your workers."
With just a few hours' notice, most of us had familiar plans in place for lockdown, but you may feel tense or a little claustrophobic in your bubble - in these situations, communication is key, MacDonald says.
"Most people will have a road map of what works for them. The important thing is to communicate deliberately with each other. Have a family meeting in the morning, make sure you all have some alone time in your schedule."
Last year we walked - and some of us ran - marathons around the block to get exercise outside. And those daily walks are as important as ever to stay healthy.
"Daily walks are really important - it's such a simple thing but so essential to get out of the house and get some fresh air. Don't let the weather put you off," he says.
Kiwis may also be increasingly anxious about catching the delta variant of the virus.
"This is difficult and it is concerning. Be gentle and validate those concerns," MacDonald says.
"Minimise your physical contact with other people. And if you do find yourself spiralling, reach out to those in your bubble. If you're in a position to support others, reach out to them."
Bring back Zoom calls with your parents, virtual Friday drinks with your friends, or a quick phone call or text to check in on each other - it's important to stay connected.
Countless resources are available online for breathing techniques or meditations that can help you manage feelings of anxiety.
It's important not to put pressure on yourself or your kids, particularly in the first day or two of lockdown, MacDonald explains.
"It's not vital that they do the school work. Just do what you can, especially over the first few days. Relax on the screen time, it's okay if they're watching TV. And take the opportunity to get out the board games or get on the floor and play with your kids."
Where to get help:
• Lifeline: 0800 543 354 (available 24/7)
• Suicide Crisis Helpline: 0508 828 865 (0508 TAUTOKO) (available 24/7)
• Youthline: 0800 376 633 or text 234 (available 24/7)
• Kidsline: 0800 543 754 (available 24/7)
• Whatsup: 0800 942 8787 (12pm to 11pm)
• Depression helpline: 0800 111 757 or text 4202 (available 24/7)
• Anxiety helpline: 0800 269 4389 (0800 ANXIETY) (available 24/7)
• Rainbow Youth: (09) 376 4155
If it is an emergency and you feel like you or someone else is at risk, call 111.