Don’t give up that positivity. It’s a great step already to talk about it. That always helps. I guess everyone has their ups and downs, partly depending on your general mental state, influenced by the people and environment around you. What helps we 100% is to self-reflect and practice gratitude. Writing about it helps to get a more objective view and makes you think more rational. Being grateful for all the good things in your life also helps to get a more positive state of mind in general. Stoic philosophy might be something you could be interested in. THE DAILY STOIC by Ryan Holiday and THE ART IF RESILIENCE by Ross EDGLEY have helped me a lot!