Your post is being reviewedWatch
If you are trying to post on anonymous or post in the mental health forum these threads will also get stuck in pre mod sometimes especially when the user is new.
If you are doing none of the above then its unfortunately likely to do with being a new account.
The pre moderation filter can be a bit inconvenient for some users but its aimed to keep the site as a whole safe and friendly
Please just be patient, if your post/thread is fine someone in the report queue will approve it for you but this can take a while if they have a lot of threads to approve