Bonjour
One mistake =
j'étais complétement mieux = J'étais vraiment mieux (much better), OR
beaucoup mieux ( a lot better)
so if tyour text as to be written masculine singular , then it's ok.
If its meant to be written by you and if you're a girl, then you have to agree the past participles when using the auxiliaire "être" in the passé composé.
With the auxiliaire "avoir" it won't change.
Le passé composé with 'être' = the past participle has to agree in gender and number with the subject.
So if "je" is feminine ==>
- je suis restée
- j'étais heureuse (heureux = masc. / heureuse = feminine)
if it had to be wrtitten masciline it's perfect (except complètement ...)
hope this helps :)