Racing heart

For the past month or so I've been having episodes at work where I feel out of breath, faint and my heart is racing. I just feel weird altogether. I've had an easy pregnancy so far and it kills me to have to stop at work and sit down because I feel funky. I hate feeling like I'm not pulling my weight.  I work in a hospital and I'm not doing any cardio at the most I'm walking around, sometimes I'm just sitting.I take my pulse and it 150+ during these episodes and it takes awhile of sitting before I feel normal again. Is anyone having this issue? I've read online where other ladies experience the same thing because of increase blood flow to babg but I haven't seen where their heart rates are as high as mine has been getting. I planned to ask my doctor but it seems like any symptom is just another thing that goes with pregnancy.