Do you want a shoujo or yaoi..cuz your title and description is conflicted.
I can give you a bunch of yaoi so cheer up :)
http://www.mangago.me/read-manga/oko_sama_star/
http://www.mangago.me/read-manga/shitteru_yo/
http://www.mangago.me/read-manga/hidamari_ga_kikoeru/
http://www.mangago.me/read-manga/samishigariya_no_love_letter/
http://www.mangago.me/read-manga/aishiteru_fujitani_youko/
http://www.mangago.me/r/l_search/?name=Nojiko
http://www.mangago.me/read-manga/yamete_kudasai_mabushii_desu/
http://www.mangago.me/read-manga/hatsukoi_wa_gunjou_ni_tokeru/
http://www.mangago.me/read-manga/marry_me/
http://www.mangago.me/read-manga/mousouka_koi_o_suru/
http://www.mangago.me/read-manga/natsuiro_moratorium/
http://www.mangago.me/read-manga/futari_no_tokubetsu_jugyou/
http://www.mangago.me/read-manga/ganbare_nakamura_kun/
http://www.mangago.me/read-manga/neon_sign_amber/
http://www.mangago.me/read-manga/given/
http://www.mangago.me/read-manga/yorimichi_kazuki_rai/
http://www.mangago.me/read-manga/thank_you_my_god/
http://www.mangago.me/read-manga/yamada_to_shounen/
http://www.mangago.me/read-manga/ichi_ni_no_san/
http://www.mangago.me/read-manga/katappashi_kara_zenbu_koi/
http://www.mangago.me/read-manga/shuuden_elegy/
http://www.mangago.me/read-manga/hatsukoi_switch/
http://www.mangago.me/read-manga/aisaresugi_confusion/
http://www.mangago.me/read-manga/aioi_musubi/
Please reccommend me a completed straight manga where girl m.c. is really and seriously insecure and depressed, and the boy cheers her up. I've been feeling really alone and depressed lately so I want to read something similar to me yet has a happy ending.