I don’t know if my messages are sending or not

If it cannot be delivered, you will get a message like this. If you were blocked, it will send, but they just won't get it and you won't know if you have been blocked.

Noobs009 wrote:

https://discussions.apple.com/content/attachment/c1645a1e-c3b6-4823-8b13-de741df2f931

This is how you know for sure if they receive or didn't receive it, you call them and ask did you get my text message.

Then you have no issue with that message at all. Like I said, if you get the Not Delivered message in red, then you know you have a problem. You won't know if a message has been received on the recipients device or if it has been read with a SMS message. You also won't get any indication if you are blocked or not. The reply is confirmation that they received your message.

With iMessage, the recipient has the option to use Read Receipts that will show you when they read your message, but those are identified with the blue text bubble and not the case for SMS messages.

Or like razmee209 said, calling them is another way to confirm with them that they received your message.