OP, I made an effort at the school gates, ignoring someone who warned me about "school mums".
I HAVE met a couple of really lovely genuine people that way.
However, I also met someone who I considered to be a good friend and basically set out to segregate me from the group, for reasons I still don't fully understand, and the emotional upset from that took me a long time to get over.
I think that because you are back in a school environment, some people regress, and you have the inevitable cliques.
I'm not saying, don't look for friends there, I'm just tying to say be wary, and also, in a way reassure you that in some respects, you really aren't missing out.
Ultimately, the thing I have in common with the majority of them, is that our kids go to the same school, and that's where it begins and ends.
I don't have many friends, but I'm big on loyalty, and would rather have quality over quantity.
I think that sometimes, especially with social media, on the outside it can look like others have loads of friends, and are having the times of their lives together, when the reality can be somewhat different.
I have quite a few acquaintances, but real, true friends, I can count on one hand , and even amongst them, I have had let downs and disappointments, but I guess that's par for the course.
I am also the person who used to make all the effort and then be left disappointed, but now I ty and strike more of a balance, have lowered my expectations a bit, and don't try and make all of the effort, because it leads to disappointment and, if you're not careful, resentment.
I don't think there are many opportunities to meet and make new friends at the moment, which can be tricky, but perhaps it's just a case that you haven't found your tribe yet.
At the end of the day, your very best friend is always going to be yourself :-)