I hope this will calm your mind some, but if it was high enough to be truly dangerous, he would have either sent you to the hospital if it was SUPER high or started you on medication immediately, if it was even in a very dangerous zone. Truly. So the fact that he’s simply saying they need to monitor it for a day means that it is outside the normal level, higher than it should be, but in NO WAY could it have been high enough to kill you. He wouldn’t have let you leave the surgery.
Also, do not focus on relaxing. Someone telling you to relax when your life is filled with stress is about as helpful as someone handing you a relaxation candle when your house is on fire... it’s just not always an option. Other PPs are correct that it’s much more important to focus on your eating and activity levels. These things will probably naturally make a change to your weight, but it’s not exactly your weight itself that’s the issue - you need to eat more of certain things and less of other things, and get more of certain types of exercise. The DASH diet has been medically proven to lower blood pressure, and it was developed by a non-profit in the US, so there is a TON of free information online about it; you don’t need to buy anything to follow it. It’s low sodium, lots of fruit and vegetables, low to moderate fat, whole grains, high fiber, lots of calcium, potassium, and magnesium. And it’s been proven that it works. It’s also been voted the best diet for weight loss by a few sources, just as an aside. Here’s a link to a page about it from the Mayo Clinic:
www.mayoclinic.org/healthy-lifestyle/nutrition-and-healthy-eating/in-depth/dash-diet/art-20048456
And here is a complete beginners’ guide that explains portions and foods to eat:
www.healthline.com/nutrition/dash-diet
This link talks about the types of exercises you can do while you have high blood pressure:
www.webmd.com/hypertension-high-blood-pressure/safe-exercise-tips
It does mention talking to your doctor if you’re not already active, but one of the things it mentions is stretching. If you’re not active AT ALL, I mean at all, there are chair stretching videos on YouTube that shouldn’t tax you enough to concern your doctor, but would still get your body to start moving. They're generally designed for older people but WHO CARES??? Any movement is good and you should feel proud of yourself for doing it, especially if you have two kids with special needs who I’m sure need a lot of time and attention.
If you want to check your blood pressure before your appointment, I would start with your pharmacist, as a PP mentioned. They can do an initial reading for you and talk to you about how high it is and maybe give you the reassurance you need that while you need to lower it, you aren’t in serious danger. Then they can talk to you about whether it might be best to come back to them for intermittent checks until your appointment, just to make sure things are on track, or if you want to get a device to do the checks at home yourself.
Good luck, OP. 
Change is difficult. But whether you start now, or you start in a month after you have the results of monitor, I suspect it will be the same: you will need to make the changes I’ve mentioned (and I’m not pretending they’re easy!) to see if they help your blood pressure go down, and then your doctor usually reassesses in X months to see if your lifestyle changes are having enough of an effect.