dear user about your question i would like to tell you that normal bllod suger have arange according to the state ....if fasting state it is 70- 126 level...in the postprandial state after 2 hours it is 80 -140 ....in the random state it is up to 200.......but in your case you have lunch then you get drowsy and sweating and these symptoms refer commonly to what is called hypoglycemia....good behaviour from you to measure your blood suger level...you found it 76 and it resemble mild decrease of blood suger level....that may happened due to hormonal disturbane or increase insulin level in your blood and you need not to worry about that as this is common problem for others also.....when stress or anxiety or severe excercise hormonal disturbance occur..and you should know that insulin hormone related to other hormones and severely affected by it......so insulin release increase and blood suger decrease and then you have these symptoms....you should avoid stress and anxiety and severe effort and you should always have sweet or choclate or juice with you to avoid this happening again ..also regular meals at regular times and dont get severe hangury will help you alot..........simply you need not to worry about that and you just need to control life style.........wish you healthy life