Yes, your landlord can do this, especially considering this is a commercial lease and so more time may be necesaary to procure a new tenant. Whether or not you have given notice, the terms of your lease may provide that your landlord is under no obligation to renew your lease under certain circumstances even if you choose to try and renew. Additionally, they will want to make all attempts to prevent the space from being empty if, if fact, you do not extend your lease term. Without having read the terms of your lease it's hard to say.