What Are The Side Effects Of Using Rx Metformin Hcl 500?

I was recently dx with diabetes I was rx metformin hcl 500 but when I take it i have multi side effects, I take reading in morning and 117 is where I usually am after taking tablet in am I check my level and it goes up befor I eat, Is this a normal response to medication. my second reading is usually 1 hour later and it shows 143?