Sinus tachycardia

I'm very frustrated, about 1 year ago I started having irregular beats with fast pulse 150. On 3rd occasion I had to have Cardioversion. Determined severe sleep apnea. Fast forward 14 months no issues. Note I was on lop resistor 25mg twice a day. Last few weeks my heart is racing, 105-120. Went to cardiologist and indicated sinus rhythm so he pushed dose to 50mg twice a day for anxiety. 1 week later I had another event mid day and was in ER. Pulse ranged from 105-120 for 7 hours but in sinus rhythm. Nuclear stress test, all blood panels good. Clap is working fine, ER doc stated everything was good and released. Went to family doc who gave me bulspar to take edge off.

If I go up the stairs my pulse races above what it should be knowing I'm on lopressor. I can tell my heart is fighting the medicine, I am afraid to do anything to throw my in that beat. My wife can go up the stairs and her pulse goes up but recovers within 5 min. I go up and I'm over 100 for 20 min another time it may be only 5 or 10 min. Another note is sometimes I smell smoke, almost like breathing in an ashtray, unknown if connected. No headaches. I ended up taking another 25mg during a bout today and it worked but it's over what I should take. I realize anxiety might be playing a bit but you can't stay over 100 beats for 7 hours straight in a hospital bed. I just am nervous what my next steps are. Anybody been where I am at

Hello,
Thank you for your interest. Im 6-4 and 298 pounds but not obese, turns out a majority of my problems was a defective sleep machine that was checked and given a fully functioning review and a week later after a second check was determined it was defective but I still am concerned a bit. My Dr prescribed a pulse oximeter which revealed low 80's oxygen levels. Went to another sleep study and my pressure of 8 needed 10. In addition it was discovered my CPAP was defective even though this was checked by the company and gave all clear. Since then my symptoms have gone away 90%. I did have my heart up doing some activity and it stayed in a constant 105 heartbeat for 30 min and eventually went down to 80. I still think something is wrong because I have this butterfly feeling in my stomach randomly and out of no where. The doctor thinks I am having anxiety over this whole event and gave me Buspar 7.5mgX2. This seems to take the edge off, no smell of smoke since the new CPAP. I have to admit I am a bit scared getting my pulse up to 100 for any reason. I am currently wearing a Ecardio monitor for 2 weeks to check for any anomalies. I almost feel like my body is leaking adrenaline so my doctor is giving me full lab blood work tomorrow. My doctor said to do everything normal while on the holter monitor including exercise and having relations so the monitor will pick this up. Any suggestions