I have 4dcs aged 7 to 2, and whilst I need a break, a great big break!, I couldn't do what you have done. Raising kids is hard, it takes a while to adjust to how hard it is. I am a sahm, dh works long hours. I didn't send my children to childcare until they were two. We have built up to two 3 hours sessions per week. That is how it stays til the dcs are 3, then they go five mornings a week. When they are ready, they go 1 or two times 3pm. This form of childcare works super well for us.
At the kids nursery (Montessori nursery, brilliant place; I've been interested in the Montessori method since I was a kid - I was a strange kid), I'd get a all if they suspected my child was poorly. They wouldn't attempt to look after my child sick, as that is my job.
Lots of differences between childcare (built up slow, you choose a warm, nurturing environment). And it may be a great prelude to eventual overnight stays in the future. Fwiw, it would be over five for me, and ideally with a sibling.
Honestly, as others have mentioned, your mum is over bearing. I'd entertain her coming down and staying with/near you and building up a relationship. Babysitting at night etc.
Our parents live on the other side of the world and visit only occasionally. It is hard, hard work. But it is not forever. Already with my oldest bring 7 and 5, I can see life becoming easier. Mil looked after our kids while they were all sleeping and we went out. Otherwise she only took the older two out on day trips, aged 6 and 4 at the time. She looks after my nieces and nephews at home, and she really struggles, usually ends up sitting them in front of the tv the whole time. That's something good childcare provision wouldn't do!