Hey there
Having lots of thoughts running around your head isn't nice, I get that & if it's similar to how I sometimes get, they're often so jumbled I can't make head nor tail of them to the point I don't even know what I feel anymore.

I notice you prefer to write rather than talk. Writing things down kind of almost forces some degree of processing what the thoughts are. Maybe you could try sitting down & just let the words flow, no matter how random you think that maybe, when you read it back there's a chance you'll see where some things might fit. Even if it doesn't, just getting them out of your head can sometimes provide the relief and a bit of mental space to not feel so overwhelmed.

I'm sorry about your break up too, it hurts I know, and will be adding to the jumble of thoughts & feelings. Be kind to yourself, give yourself time & permission to feel however you feel about it, the loss of a relationship is like any other loss and takes time to get over and deal with emotionally.

Finally as happy & confident as your colleagues may appear on the outside, it doesn't necessarily mean that is the case. People in general are very good at putting on a front for the rest of the world when behind closed doors things are not so good. You may be comparing yourself to false fronts. Please don't ever think you're alone in how you feel. You only have to read through the posts on here to see all nature of things people are wrestling with and trying everyday to cope & make it through. Many of those posting may be like me to the rest of the world all is well. Only a handful of very close friends & two family members know the truth of my ups, downs, struggles and mental battles with myself. Well that small group & the community here! But that's where posting here comes in. I can be me and be accepted as I am & get help into the deal.

I wish you all the very best & send you hugs.