There is only one test.streamingworld.us.pem file in the haproxy cert folder.
I use the same basic haproxy config for all my websites with no issues. Here's how I renew a cert:
Within the haproxy container, I do:
certbot certonly --cert-name test.streamingworld.us -d test.streamingworld.us
cd /etc/letsencrypt/live/test.streamingworld.us
cat fullchain.pem privkey.pem > /etc/haproxy/certs/test.streamingworld.us.pem
restart haproxy
Here is a site that correctly uses a renewed cert. The website does nothing, but you can see SSL is working: https://www.streamingworld.us/