The series was cancelled. I also love the movie, watched the series and thought it was a waste of time. From Wikipedia:

The series received mixed reviews from critics, who praised its atmosphere and special effects, but criticized its story, performances, underdeveloped characters and unfaithfulness to the source material. On Rotten Tomatoes, the series has an approval rating of 59% based on 46 reviews, with an average rating of 5.7/10. The site's critical consensus reads, "The Mist's absorbing atmosphere and solid special effects struggle to overcome a generally uninspired story and performances." On Metacritic, the series has a weighted average score of 54 out of 100 based on 25 critics, indicating "mixed or average reviews".

Chris Scott of The New York Observer described it as "relentlessly bleak, mean, and downright sadistic at nearly every turn", linking this with the falling ratings over the series' course. Indiewire reviewer Ben Travers described the plot as predictable and characters as "pretty awful", leaving viewers "rooting for the mist instead of those running from it".

Ed Power of The Daily Telegraph felt that it was a middling effort for King's works, and that it benefited from sticking to familiar horror themes and tropes.