Nginx proxy, WP on Apache. Redirect 302 on wp-login.pphp

I'm using nginx to proxy traffic to Docker containers, but I'm having problems with a container running WordPress over Apache.

Blog works fine, I see posts, pictures... But I can't access the admin page because the redirection to wp-login.php is returning a 302 and never is done, so after some tries the browser throws an error about too many redirects.

Proxy config:

server {
    listen 443 ssl;
    ssl_certificate /etc/letsencrypt/live/domain.tld/fullchain.pem;
    ssl_certificate_key /etc/letsencrypt/live/domain.tld/privkey.pem;

    # HSTS
    add_header Strict-Transport-Security "max-age=31536000; includeSubDomains" always;


    location /newWeb {
        proxy_pass http://127.0.0.1:8080;
        proxy_set_header   Host $host;
        proxy_set_header   X-Real-IP $remote_addr;
        proxy_set_header   X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header   X-Forwarded-Host $server_name;
        proxy_cookie_path / "/; secure; HttpOnly";
    }
    location /blog {
        proxy_pass http://127.0.0.1:8080;
        proxy_set_header   Host $host;
        proxy_set_header   X-Real-IP $remote_addr;
        proxy_set_header   X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header   X-Forwarded-Host $server_name;
        proxy_cookie_path / "/; secure; HttpOnly";
    }
}

server {
    listen 80;
    location /.well-known {
        alias /usr/local/etc/letsencrypt-webroot/.well-known;
    }
    return 301 https://$host$request_uri;
}

Notice that I'm not looking for the try_files directive to prevent the loop, I'm trying to find the solution to successfully redirect to wp-login.php.

UPDATE:

This is from the Docker host. 8080 is the port I'm forwarding to Apache's 80.

wget http://127.0.0.1:8080/blog/wp-login.php
--2016-10-25 11:35:34--  http://127.0.0.1:8080/blog/wp-login.php
Connecting to 127.0.0.1:8080... connected.
HTTP request sent, awaiting response... 302 Found
Location: https://127.0.0.1:8080/blog/wp-login.php [following]
--2016-10-25 11:35:35--  https://127.0.0.1:8080/blog/wp-login.php
Connecting to 127.0.0.1:8080... connected.
OpenSSL: error:140770FC:SSL routines:SSL23_GET_SERVER_HELLO:unknown protocol
Unable to establish SSL connection.

I understand the error is because Apache is not listening on HTTPS, just HTTP. Which leads me to two questions:

• How the hell can I have SSL offloading with Nginx and Apache? In theory, Apache doesn't need to expect HTTPS.

• In the wgetexample, why is it being redirected to HTTPS? It's not going through nginx, but directly to the Apache container, and VirtualHost is just the simple:

  <VirtualHost *:80>
      DocumentRoot /var/www/html
      ErrorLog ${APACHE_LOG_DIR}/error.log
      CustomLog ${APACHE_LOG_DIR}/access.log combined
  </VirtualHost>
  

  There is no .htaccess either