Weakness and diziness. I can recover.

From last couple of weeks, i have been experiencing heavy dizziness and weakness after evening starts. Drinking coffee temporarily helps but sooner or later that weakness comes back. I am very active during daytime , wake up at 7 am, go to mixed martial arts training, go to office on my bicycle, actively work in office and take some food every 2-3 hours,sleep for 6-7 hours, meditate for half an hour everyday and laugh hard on every funny occasions :). I rarely masturbate , eat lots of healthy food like fruits, almonds , dates etc and engage in indoor sports well (like tt, foosball etc). On last checkup i found little knee problem because of my overweight built and much engagement in sports for which i take a prescribed medication every night from last month. My bp was 70 on the downside during last checkup which might be low. Please suggest how i can recover.