Starting Point of Stress

I'm staring to have some teaching depessions. it feels like hell when the class is noisy then it gets even worst when it is the time of assessment and neither of them even get 50% the quiz. Do I have to lower my standards? Or am i That not effective? Anong problema sa akin? Ang alam ko lang, it's my voice because it doesnt sound authoritative. But, I see to it Im implementing the class rules to make sure that the class is well-regulated. I even get tired easily. Is it nutritional problems or it's just that I can't handle teaching anymore? Lord please, I love this job, give me more strength, skills and determination to surpass these unlikely  things that's happening on my teaching experience. I know the reality of being a teacher but it;s getting my nerves. I feel frustrated on myself, and on my students. Lord, please, give me more enthusiasm. Make my students feel and apprecite the importance of education in their lives. Give me more motivation so that I could stand all those problems Im encountering and tye ones i have to encounter. Lord please, teaching is really my life. I do'nt want to reach the point where I would regret what I have entered. Lord, you put me here so let me stay here.