Feeling cold can be a sign of being unwell, lack of sleep, lack of suitable clothing, and also may be a symptom of having a problem with your thyroid gland. Feeling cold can be a symptom of an underactive gland.
Make an appointment to see your doctor who will no doubt run some blood tests, for low iron levels (that would indicate anaemia as mentioned by hannahsmama13721) and also to check your thyroid levels.
You may be anemic... You can get a blood test from your doctor to find out
U R FREQUENTLY INFECTED BY SOMETHING RELATED WITH COLD, AND USE BOILED WATER TO DRINK AND TAKE AYURVEDA MEDICINE " CHAYAVANPRASH LEHYAM " TWICE PER DAY. IT WILL INCREASE UR IMMUNITY POWER AND IT ALSO IMPROVE UR HEALTH