We will never know the future, let alone coins like Doge, even in Bitcoin, people never know about this. In the past, many people got Bitcoin from mining, faucets but they sold them cheaply, some were even very famous for buying two pizzas with 10,000 BTC, all because they couldn't predict the future, so it is with Doge. Regret should not be remembered all the time, but make that regret a valuable experience and make it a lesson to take advantage of every moment so as not to miss it.
The last sentence you said is very beautiful and will motivate us. That in the crypto world there will always be opportunities as long as we don't stop trying and keep up with the development of the coins we want to invest in. But what needs to be emphasized is never to be disappointed with what happened in the past and don't be too obsessed with what happened because otherwise, you will also be trapped like many people who buy memecoins that are popping up and hope to be like doge coin someday but what you get is a loss. So you still have to be careful in investing in memecoins.
For Bitcoin, it must be understandable because it was the first cryptocurrency but after Bitcoin a lot of coins have been created and some experience the same thing. That should have taught us a lesson already.
The phrase "never stop trying" can also be applied for those who don't stop holding and hoping that their coins will give them a fortune someday. Dogecoin is still a good example for this and also if we didn't let our fears or greed overcome us. We are only humans and emotions like the OP experienced is only normal and may not be totally avoided. What important is that we need to snapped and go back in reality as early as possible.