Splunk web not loading unless specify port 8000, now going down all together

So I'm very much not an export on these things, but I think something has gone horribly wrong with my ports....

about a week ago my splunk we stopped loading unless I explicitly specified the port in the URL like

http://myurl.com:8000/en-US/manager/search

I'm not periodically having splunk web go down all together and getting:

503 Service Unavailable

Return to Splunk home page

The splunkd daemon cannot be reached by splunkweb. Check that there are no blocked network ports or that splunkd is still running.

When I check what ports are being used (with netstat -a) I see none of the normal localhost:8089 lines. I can restart Splunk and have it come back up fine (well using port 8000...) but it will go down again seemingly randomly.

Any help (or where to start looking / googling) would be great.

Thanks