Anxiety Issue?

[Sqwrl]

I hope someone might be able to help me as I haven't had any luck with the doctor. For the past two months I have started having this feeling at night (not every night) where I'm just dozing to sleep when I get this feeling in my gut that radiates out like a flushed feeling. Kind of like that feeling where you think you are getting ready to vomit but my stomach doesn't hurt. It's just a feeling of something wrong and then my heart starts beating really hard but bp is ok. The past two nights have been the worst. Last night I actually woke up from sleeping with this feeling. I woke instantly and had to get up and walk around to calm myself. Tonight every time I started to doze off, I would start getting this feeling and wake up. I haven't been able to sleep at all tonight. The only medication I'm taking is bp medicine and not a very high dose of that. The doctor took labs that came out normal and did a heart monitor for a couple of days that turned out normal. The doctor wants me to do a sleep study but this hasn't been happening every night so not sure how effective that will be. I have recently lost about 60 pounds and have been exercising every day so I feel I am the healthiest I have been in a long time. I have never suffered from any kind of anxiety disorder but have had bouts of depression but not recently. Can anybody help me, I'm at my wits end!