Feeling Dizzy/ Lightheaded 1000mg Metformin

I have taken 500mg of metformin for a year now, my doctor upped my dosage to 1000mg and I started feeling lightheaded. Instead I decided to go back down to 500mg taking it at night with a meal but I still feel lightheaded during the day? I’ve never experienced this before and have seen that it is common symptom any tips for helping with this! I’m currently a college student it is significantly impacting my studies :/