How do I know if I am being reasonably anxious about something, or overreacting?

Try to think about the worst possible result that could possibly come from the thing you are anxious about. Go ahead and go big at first, doom and disaster and end of the world. Decide if that's a logical or likely outcome, even if things go really wrong. Start whittling down your worst possible outcome till you've got something with a reasonable likelihood of actually happening if things go badly. Looking at that outcome, is it dire enough to justify the amount of time you have spent worrying about it? And if it is that dire, has the energy you've expended on worrying about it made the outcome less likely? Reasonable anxiety is the sort that spurs you to take greater care and make sure you're doing everything possible to avoid the bad outcome. When anxiety moves beyond that, it's probably time to start taking steps to manage your anxiety.

You need to know what triggers your anxiety, once you do, you need to find ways to cope with it. If you get anxiety symptoms like sweating, shaking and your muscles get tense and even nausea over some unfamiliar situations that people don't find.. stressful, it doesn't particularly mean you're overreacting. Some people are more sensitive than others, so it would never define it as overreacting, it's just how you, yourself react to it. And you can have control over those situations again but you need the right support and guidance from your close friends or family. If very severe, professional help.

I turn to the “the big 5”. These are questions you ask yourself about your anxieties. Think of your situation and ask yourself, 1) what are the chances of that happening? 2) What is the worst thing that can happen? 3) Am I right to think that? 4) The 5 year rule. When I look back on this moment in 5 years time, will it matter anymore. Will it be significant or will I have forgotten all about it? 5) What is this worth? Is it worth worrying over? After you’ve thought about these questions your mind will be clearer and you should be able to assess your situation and see whether you were overreacting or not.

- Ask yourself "is this my Logical Mind speaking or is this my Anxiety speaking?" - Validate your own feelings by saying "No matter what the reality is, my feelings are still valid. I have a right to feel this way, no matter what. My feelings are mine, and no one else can tell me how I should feel." - Make a three column chart. In the three columns write: 1) What is the WORST that can happen? 2) What is the BEST that can happen? 3) What is MOST LIKELY going to happen? - Do a grounding exercise to make sure that you are in a state called "wise mind" when you make your judgement. - Try asking a trusted friend or family member to evaluate the situation for you.

if its something that is important to you and youre anxious about the outcome because it will greatly affect your way of life or anything like that, it is reasonable. if you are severely anxious about something in which the outcome has no affect on your life, meaning whichever way it goes you are able to continue your life as you know it, then it may be unreasonable anxiety and maybe you are over reacting. Everyone is entitled to their own way of dealing with things, but if you are affecting a relationship with someone else over a reaction that you will regret, maybe its important to think twice about it.

if the situation is to be judged and you are doing efforts to understand it but it is making you reacting instead of responding then you are being anxious.

You don't. That's the hardest part. You may think it's reasonable or that you're overreacting, but the point is: it's different for everyone. A breakup can be as triggering as the passing of a loved one. If it affects your life negatively: you should do something about it. As little or big as the problem may be. Anxiety doesn't go away by itself, it takes some courage to recognize and accept that it affects you, and to take action.

It's a very tough question and I'm still struggling with it but what I try to do is try to view a situation "objectively" by thinking of another person in the same situation with the same things happened to him/her and evaluate whether or not that person should feel anxious. I know it sounds a bit dull but it helps me to disconnect mysel from the equation. Also, if you have friends you trust you can always ask them if you are overreacting.

There may be some signs of anxiety. Trembling, twitching, shaking, etc. some signs of overreacting could be seen as someone who you usually arent and act differently.

There's a reason you're feeling that way. Follow that feeling and explore it. Question why you have that feeling and talk to someone you trust.