What's the adjective I can use when my English skills (or other skills I've been working on for quite a long time) are not improving and depressed about it? For example:
Lately, I've been feeling adjective because I feel like my English is not improving.
What I want to say is something like depressed or exhausted, kind of feeling you have when you doubt about yourself and you're stuck at the same level, but none of those words seem natural.
I've also looked up some synonyms, but sad or gloomy seems too strong and I'm not sure about low or down. Are those right words?
I wanted to ask for a proper word I can use in this context.