IPhone calendar notifications go away too quickly?

On my iPhone calendar, I'll occasionally set an alert to go off when I'm busy or asleep. By the time I've checked my phone, the notification is already gone. This problem has caused me to miss several important events. Is there a way I can fix this? If not, is there a calendar app I can download with more permanent alerts that force me to click "okay, I've seen this" before they go away?

All the ads above are scams. They will all try to sell you things yo DO NOT NEED - what you need, is self-education about your phone. If you sweep down the screen on your phone, you will get the events and other things you designated to appear there - and at the top, there's another choice - "Notifications". They will all be there. In fact, you will want to clean them out periodically, because you might have so many, that they pile up. In Settings, you can decide what goes there, and what does not - but I think you know THAT part, already. Go check now -see if old ones are there. Also - you might want to have things in Reminders, or have then entered in your Calendar (some sites, like Marriott motels, and airlines, will do this if you click to *send to my calendar*.) I do not think you really know how to use all these features on your phone - there's a guide you can download, and save under BOOKS on your phone - and learn a lot of things. There are also ample sites online - many are related to phone and computer magazines - that also have great s articles and tips. I have learned a ton - my husband just says "Honey - can you fix this for me?" Then it becomes HIS turn to make dinner, or take me out.