Your wireless signal from your computer to the gateway may be strong but there are many things that could impact your service.
I would recommend starting here: https://www.telus.com/en/bc/support/article/cant-connect-to-the-internet
If that doesn't work, I'd recommend contacting technical support by phone.
If you are seeing speeds that slow, there is indeed something needing to be fixed. Fibre connections usually exceed the advertised speed. Instead of waiting on the phone, Telus’ social media team can assist you with your questions. Reach out to them via Facebook Messenger or Twitter by tweeting @telussupport. You can also call using the numbers in the ‘Contact Us’ section at the bottom of the page, or, if on a computer the Chat function listed there as well.