Hello, 
It is commonly seen that patients suffering from RA have low 
testosterone levels while 
Methotrexate may cause low testosterone levels in men with 
sleep deprivation (due to increase in IL-1β which reduces the production of 
Leydig cell production of testosterone as found in research studies).
cal conditions that cause low testosterone levels are thyroid issues, liver, kidney or pituitary problems, obesity or 
weight loss, smoking, alcohol, drug abuse or addictions if any.
 Get clinically assessed get treated at the earliest. To increase testosterone levels naturally do exercises & weight lifting, take proteins, vitamin D & mineral supplements, nuts, dry fruits, minimize stress & take quality sleep.
Hope I have answered your query. Let me know if I can assist you further.
Take care
Regards,
Dr Nupur K, General & Family Physician