Can anemia make my period shorter? (i had a one day period, bled once only) my haemoglobin came out to be 6.3, is this the reason for my short period

Short & long story. Your short period at 6.3 hemoglobin may be a "survival" mechanism for this "long story". When the blood level of red blood cells plunges to this low level, your ability to carry oxygen to the peripheral tissues diminishes greatly.As a result mother nature will try to "conserve" red blood cells lost during your period. I hope you are seeing a md to find the cause and are taking an iron supplement.