Ser Vs Estar

[fglorca]

Thanks so much for all your help, it is really appreciated.

I bought the shirt, returned home, tried it on, looked at myself in the mirror, and then realised it was too big (grande a better option, I see now!).

Apologies, I should have given more context with my original post, in future, I will do this.

I know I have heard both era and estaba, but I'm not exactly sure of the difference in meaning with these two in this particular context.