Suggest Treatment For Anxiety And Slight Palpitations

Question : Hi :) I have a question. I am driving myself crazy googling all day and just making myself more crazy. For the past month I have not been feeling "myself" I do suffer from occasional anxiety. I am 39 years old in pretty good shape and I eat pretty good however, I am a smoker. From about April, I have been getting my monthly cycle approximately 15 days apart as opposed to my usual 28 day cycle ( like clockwork). I went to my gynecologist and I was sent doe a sonogram of my ovaries and I do have cysts. I then went to my internist for routine check up and cardiogram, all went well. While I was there, I explained to her that I just don't feel like myself. I feel more than your occasional anxiety. I feel a throbbing in my throat at times and slight palpitation very briefly. I feel very tired and just a weird " confused" feeling at times. She took my blood and I went to speak about my results yesterday. She told my that my thyroid level was low. I have the blood results in front of me and they read TSH 0.25 next to it, it reads reference range 0.40-4.50. She gave me a referral for an ultrasound of my thyroid and said that this can contribute to how I am feeling. Is this reading really bad? What will they be looking for in the ultrasound? Is it true that this can contribute to how I'm feeling. Also, as I was sitting here reading my results, I read that my carbon dioxide level is 16 with a reference range of 19-30mmol/L. What does this mean? Do I not have enough oxygen in my blood? Is this bad? She didn't mention this to me. Then under the test name of LD it says 384 with a range of 100-200 what is this LD test for? I'm such a nervous wreck. Can you please help explain to me. Thank you...