High blood pressure low blood pressure and fast heart rate?

I'm 22 years old, female and a new mother to an 11 month old little boy, read carefully! When i turned 17 and became ually active, my heart rate would go rather high after getting up in the morning or sitting for a long period of time, I would feel dizzy and feel faint. It's been a few years and now that I'm 22 I still have the same issue but it also happens when i wake up with my son at night. I have had the holter monitor and my doctor has seen my pulse skyrocket when i write down symptoms. I have been feeling randomly nauseous and dizzy, mostly at night for about 2 months now (I'm not pregnant) I just started a trycyclen lo a month and a half ago and have had one cycle. The last three mornings I have been not feeling well.The first morning I got to work and checked my pulse, it was fast so i checked my blood pressure, it was 152/100 pulse 116 (i have counted 130-140 at times) I went home because i was feeling so ill, I don't usually have high blood pressure, in fact my doctor thinks my fast pulse might be caused by extremely low blood pressure. The next day, went to work, same thing happened it was 141/91 pulse was 120. The next morning at about 940 am i woke up with my son and felt my pulse race extremely fast, i had to go sit down so i wouldn't fall over then i felt really sick, it got progressively worse until i threw up and could not keep my eyes open and could not stand up on my own. I went to Emerge and they ran blood tests, urine tests, and an ekg, all came back fine...My blood pressure dose go pretty low sometimes although i really don't know when an episode will happen so i haven't checked my blood pressure before my heart races...What do you think it could be?? I'm really tired of no answers