When you say 138 links I'm going to assume your site has 138 pages and only 43 pages are being indexed. If not, let me know.
Have you submitted an XML sitemap with all 138 pages? If you have and still only 43 are being indexed, I'd take a look at the quality of your pages. If you have several pages that have similar or duplicate content, Google may decide to index only one. Also, make sure all 138 pages are easy to navigate to from either the nav bar or an HTML sitemap (or both).
If all else fails, try the Fetch as Google tool within Search Console to submit your non indexed pages and then click submit to index. I usually find this rarely does anything, but it's worth a shot.