Another Canuck here, other coast though lol.
I have had a few concusions in my 20 some odd years. To the point my doctor recently looked at me and said "Okay NBE enough is enough, you can not afford to keep beating your head off the ground". To which I blankly stared at him going "umm try telling that to my bratty mare"
My last one was when bratty mare decided that she had enough of the jumping and Mommy needed to do the jump herself first *eyeroll* Needless to say I made a wonderful lawn dart landing on my hand and seemed to have boinked my head after my hand took the impact. I didn't even realize I hit my head then looked at my helmet and there was a big scratch down the back of it, so apparently I hit my head. I got back on and finished my lesson as it was a clinic and I wasn't leaving mid way through a $100 lesson.
Come to find out later after my friend made me go to emerg I had a nasty concusion and did some serious damage to my wrist.
I do still get a bit nervous getting back on after having a serious fall and honestly, I would be scared if I wasn't
a little nervous. Its a natural feeling and once you are back on you will be fine. Its just the whole process of swinging your leg over the saddle then you feel right at home and you get that natural feeling of being where you belong.
As for how long it takes to get back on, I follow doctors orders on that. If you have a bit of a black out I would take a few weeks as you made your brain kind of slosh a bit which likely caused a bit of bruising to your brain. If I have enough of a concusion that I had a small black out moment I will take 2 weeks off or so. Your brain is very important for obvious reasons so you need to treat it well!
As for helmet, yes it needs replaced. A lot of "brands" will actually give you a discount on a replacement helmet if the fall is before it expires. I would call them and see.
I've never been able to send mine in as I seem to be lucky enough to go a decent amount of time between falls and my helmet is usually expired by that point, or I will just forget.
Rest up and take it easy! And follow doctors instructions.