It can be common for diabetics to have blood pressure issues- more commonly high, but sometimes low as well. Here's a list of somethings that can be used to treat low blood pressure- it's good to get your doctors take on what you should be doing and what might be contributing to the low blood pressure, it's important to identify the exact cause.
• Drinking more fluids
• Adding more salt to your diet
• Avoiding or limiting alcohol
• Wearing compression stockings
• Taking certain medicines, such as fludrocortisone or midodrine (Orvaten)
• Going very slowly from a sitting to a standing position
Hope that is helpful!