Is it normal to feel worse months after a break up, rather than imminently after

Just asking because I (20, M) was dumped by ex (F, 19) over text about two months ago after being together for six months and idk man.

It's not like I'm thinking much about my life, I've got a clear career in mind, just finished with uni this month, don't over indulge in drink, 5"11, dress well, act nice all that stuff. My mum hated her and she didn't stick around long enough to meet my dad. We met on Hinge, I met her parents who didn't like me but I liked her.

There's no need for me to have her constantly on my mind, but I don't know why it's now instead of before. My dad was probably right when he laughed it off as stupid, and my mum was probably right to not get attached to her because the travel distance was an hour.

I just feel like now I can probably drive to Glasgow and I've finished uni there's no need for us to still be broken up but she disagrees. Which is fine. I can't force her to date me but I solved the problems of the relationship that she outlined before breaking up with me over text.

Does anyone else feel worse ages after breaking up rather than imminently after? Is this normal? It was my first long term (though does 6 months count as a long term relationship when you're 20? My parents don't think so and think I'm retarded for thinking like this) relationship.