Is There Anyway To Get the Item Number of an Collection Item?

Yes, you won’t want to rely on the row numbers of the collection as they aren’t always going to be the same depending on your query and what’s returned as you’ve mentioned.

If you require an order to your data, one idea is to have a field that contains this value so that no matter where the row falls in the query result you can use that field to maintain the order

There are likely other approaches too.