Is this a panic attack?

Is this a panic attack?For as long as I can remember I have been getting these emotional pangs that last 10-60 seconds and then fade away.I’ll be happy or relaxed and then suddenly, and it is very sudden and noticeable, I will feel indescribably shitty. Like absolutely disgusted and dreadful. It feels like a pit of despair. Everything happy is just violently ripped away from me.I didn’t think it had any triggers but I notice it coincides often with nostalgia, but it is very distinct from nostalgia. It isn’t restricted to nostalgia either. It’s awful and fast and can really ruin a good moment. I’m not a doctor but it truly feels chemical.My heart doesn’t start beating really fast, and I don’t really have any negative thoughts and it feels less like anxiety and more like hatred towards existence.It’s not regular depression either because it’s very sudden and fast like a big drop. And then it goes away a little less fast.Does anyone else have this or know what it is????