?????not all alerts come up :/

🎀mummy🎀 • Aussie!!🇦🇺 Mother to two 💕
So not all alerts apear when my post gets posted on, it said i had one comment and i had gotten 7.... like 5 hours ago, and then i closed the app and it said i had no new alerts so i opened my post And there was 4 new ones over 5 hours ago again :( i must have missed out on soooo many comments over the last few months that sucks...