Database Error (some tables don’t exist after upgrade)

Hi guys. after upgrading to 2.3 using wordpress automatic upgrade plugin, the wordpress thing let’s me create new posts and pages but won’t let me edit. When I try to edit a post, this happens:

WordPress database error: [Table 'pinkptc_neopets.wp_post2cat' doesn't exist]
SELECT cat_ID AS ID, MAX(post_modified) AS last_mod FROM <code>wp_posts</code> p LEFT JOIN <code>wp_post2cat</code> pc ON p.ID = pc.post_id LEFT JOIN <code>wp_categories</code> c ON pc.category_id = c.cat_ID WHERE post_status = 'publish' GROUP BY cat_ID

WordPress database error: [Table 'pinkptc_neopets.wp_post2cat' doesn't exist]
SELECT cat_ID AS ID, MAX(post_modified) AS last_mod FROM <code>wp_posts</code> p LEFT JOIN <code>wp_post2cat</code> pc ON p.ID = pc.post_id LEFT JOIN <code>wp_categories</code> c ON pc.category_id = c.cat_ID WHERE post_status = 'publish' GROUP BY cat_ID

Warning: Cannot modify header information - headers already sent by (output started at /home/pinkptc/public_html/neopets/wp-includes/wp-db.php:160) in /home/pinkptc/public_html/neopets/wp-includes/pluggable.php on line 390

Is this happening to anyone else as well? Unfortunately I didn’t backup when I upgraded -_-