I Recently Was Taking Generic Hydralazine Hcl 100 Mg And

I recently was taking generic hydralazine hcl 100 mg and now the drug store changed manufacturer. The previous pill I was taking did not give me headache, I had no problems. This pill give me headache, taking this pill about one week and half. My blood pressure at this moment is not as good since I started taking this pill. I am told that this "medication is the same but different color, size or shape may appear different". Are all generic drug the same as other manufacturers.