Restarting PostgreSQL 10.1

I'm kind of new to PostgreSQL and I'm having problems finding how to restart Postgresql. I've been using Postgresql on the system for some weeks at least but all of sudden I couldn't connect any longer. I'm running Postgresql 10.1 on macOS High Sierra using pgAdmin3.

From my search I noticed postgresql is no longer running or listening on port 5432. I checked the logs and I noticed the last items on the logs show:

LOG:  received smart shutdown requestLOG:  worker process: logical replication launcher (PID 519) exited with exit code 1LOG:  shutting downLOG:  checkpoint starting: shutdown immediateLOG:  checkpoint complete: wrote 0 buffers (0.0%); 0 WAL file(s) added, 0 removed, 0 recycled; write=0.003 s, sync=0.000 s, total=1.316 s; sync files=0, longest=0.000 s, average=0.000 s; distance=0 kB, estimate=152 kB

I can't recall stopping postgresql. I've been looking for how to restart Postgresql but the options I've seen online don't seem to solve the issue.

Any help will be fine because I don't want to have to reinstall postgresql and lose data from the earlier installation.
Thanks.

Mac O.