5-htp caused similar problems for me, at only 50 mg p.m. dose (dry mouth, low BP, weakness, daytime fatigue, waking up early a.m.). A Dr. Michael Gerson at Columbia has done extensive research into serotonin overload using 5-HTP as it affects enteric serotonin receptors and notes that these effects are known reactions, not just adverse effects but exactly what 5-HTP (and Rx SSRIs) do.
The fatigue I had led to lack of exercise, which contributed to joint and muscle pain, weakness, and I also had weight loss from the 5-htp with loss of muscle mass.