Thank god I found this post! Can I vent/ramble too?

I've become so hypersensitive that even I realise at the time that it's irrational and unfair on others but I cannot stop the tears from bubbling up, cannot stop my voice cracking. For example, my boyfriend made a passing comment to a friend of ours about relationships in general, wasn't a reference to us, and certainly didn't apply to us in that context.
However, I couldn't get it out of my head, it looped my mind for hours, I didn't want to cause a scene, however both of them noticed. I cried for hours and hours, and when I finally told my boyfriend, he was upset and confused. He reassured me that it wasn't about us, that he loved me, that I was being stupid. But saying that killed me, because, while I knew I was being stupid, I didn't want to be told it.
This has lead to be me becoming quite withdrawn and upset, and I'm now constantly wary and find it harder to make conversation with him..

I realise that it's easy to say that he's not being very understanding or supportive. But, he has been my rock through this. We'd been together for 18months when I got my first concussion, and he's stuck by me. He's been to thousands of hospital and doctors appointments, argued that I am suffering and that there is something wrong while so many people were sceptical.

He has been brilliant. And I wouldn't have coped without him. But now, I know he's finding this hard, and I don't know how to deal with this myself. I don't know how to make this easier for him... How can I support him when.. Do I need to get some help to deal with my emotions for both of our sakes? Oh, I don't know. But I feel better for getting it off my chest. Thank you. Sorry, that's a hugely long rambly message!