It's not wrong to think that you need a website. If you're a professional it is expected that you have some sort of online presence, typically taking the form of a website. What is wrong is to simply think that you need a website without asking why you need that website.
Nobody actually wants to use your website. What they do want is the outcome of using your website.
It feels silly to ask a client why they need a website. Sometimes the answer may seem as obvious as "we only sell our products online, how else would we do it?". But the solution isn't always an eCommerce website. The solution may be a Facebook store because your customers are more likely to buy through that medium.
Side note: Facebook do charge a 5% fee for sales through their platform, but this is not much higher than the commission taken by most other eCommerce platforms and payment providers (Shopify and WooCommerce up to 3.9% + 30¢, Webflow up to 4.9% + 30¢). This is without even considering setup, hosting, and maintenance fees.
The importance of stepping back
What I'm getting at is the importance of not rushing into a website before you understand the result your audience want and finding a solution for that. Too often is content just thrown at the designer who lays it out onto a page without any concern for the end user. It might look beautiful and work like a charm, but is the person using it getting the best result for their time?
What does your audience want from your website?
Do you know what your audience is looking for from your online presence? It's not easy to answer this question, but you can make some educated guesses. Visitors of websites for a:
Restaurant would want to see what the space and food looks like, the location, opening hours, and price list. Their secondary goal is to book a table, either by phone or a handy booking system.
Accountant would either want to get a feeling of whether they can trust you to handle their finances and get a feel for your team's character, or to find out more information about what services you offer and how to contact you.
Estate agent would want to find a property that fits their requirements or get details on how to sell/let their own property through you.
Online shop would want to easily browse and purchase the available products, without having to jump through hoops to receive those products.
Digital agency then the reality is most people want to know how much you might charge before getting in touch (subtle plug) and to see some of your work or client list to validate your reputation.
What should you do now?
Take a look at your website and ask yourself: Is this serving my audience appropriately?