8 weeks tomorrow

Tomorrow I'm 8 weeks pregnant and I go see the nurse for my medical history appointment, I also get my thyroid checked since changing my dose to 75 mcgs a day. I feel weak at times, morning is my best time and afternoons and evening leave me gross feeling. I keep getting these spells where I feel out of breath, and my heartrate is 100 bpm and today it was really racing at 120. So I'm interested to see what my thyroid is doing. When things simmer down my heartrate is closer to 80 bpm. Also Mitch, Dad and I have noticed while taking my pulse that it is irregular, it will beat beat beat, wait, beat again and or wait beat slower then speed up or skip a beat or what not. This has been going on for longer than I've been pregnant (the irregular part) and I plan on talking to the nurse about it and I don't know if it's anything to be concerned about or not. I just feel tired and weak and my stomach hurts a lot but I'm thankful I don't feel pukey. The 1st trimester would go a LOT faster if I felt good....