If you are just waiting around to see what happens, its probably the best time to dig in and reverse engineer what is happening.
The first step is to establish what pins under your account and your URL's (Domain) appear under Pinterest for /source/yourdomain
Normally if you are ghosted, pin reports bombarded, marked as spam, or domain banned you will immediately spot some areas that need attention under the account or within the account email.
Account email is usually pretty telling when bad things are happening if you are opted to receive account emails, and suddenly around the date of the drop off stop receiving the daily updates, or pin/save info. This is a sure sign something is not going right.
You might even spot some juicy emails from Pinterest describing the issue, or related to repeated copyright claims and removals.
Using a combination of Google Analytics reporting & Pinterest reports you should be quickly able to report and export data before, during and after the drop off in traffic.
Here you want to take a look at some of the top pins for traffic (life cycle) before, during and after. Then drill into how you are being placed within Pinterest for these Pins.
Did they rank and are now nowhere in sight? Did some but not all Pins decline for traffic after the drop-off? What makes those receiving traffic still so special?
Using Pinterest search + "your keyword" + "your pins" in the dropdown, you can quickly identify if Pinterest views your Pins as categorized under any given keyword that you optimized your pins or boards for.
If all still seems fine, you may want to check the obvious which is the user path to your domain by using an alternative account on desktop and mobile. Broken links, dodgey Cloudflare installs/page rules, domain backdoors, malware or generally not seeing the same things while logged in as other users can all play a part in the decline.
If this seems a bit too much to get into, take a leaf from
@memovlad and simply reset and go again.
I would only advise the above if you actually consider it to be worth the time and effort for any given account. Perhaps making a new account, new boards, pins, and domain could better serve your time?