Final answer:
The potential diagnosis that most closely fits the patient's overall symptoms is insomnia.
Step-by-step explanation:
The potential diagnosis that most closely fits the patient's overall symptoms is insomnia. Insomnia is characterized by a consistent difficulty in falling or staying asleep, which aligns with the patient's difficulty sleeping. Patients with insomnia often experience long delays in falling asleep, waking up several times during the night, and having trouble getting back to sleep, which could explain the weight loss, profuse sweating, and increased heart rate that the patient is experiencing.