Loosing apatite and losing weight. Could it be psycologiclly?

Possible. If a full history and physical is done and xray, labs, stool samples, egd etc is done and no other explanation is available then an eating disorder is a reasonable option. There are experts in the field and a referral to one for an eval is reasonable.
Go see your DR for a. Comprehensive exam. Could be related to stress, anxiety, depression, thyroid problem , tumor etc. Hope all is well! god bless u!