Whoever thought it was a good idea to encourage people to take online tests as a way to take care of their mental health, I hope you know you made things worse. Taking Psychological tests w/o a trained & licensed professional can only do more harm than help.
DASS-42 (and the shorted DASS-21) is a measure of emotional states and can never be the sole basis for diagnosis. Even if you get an extremely sever score, it does not equal to having a disorder. Our emotional states really vary depending on situations.
Psychological Test Scores are not the only basis we use to diagnose. It takes more than that. Also, although DASS-42 is free and available on public domain, it is intended to be used by trained professionals. Not all tests online are also valid and reliable.
Test scores are and should always be interpreted based on many factors and the context why it was administered.
If you want to take those tests to learn about yourself, please know that freely available online tests may not always be valid or reliable. Don't take the results as is. It would still be best to speak to a professional and be guided.
Some online tests can also do harm on standardized tests as this affects their validity. Creating those tests takes years of research and several processes of validation and standardization. Misuse of them makes them worthless and can rendered them invalid.