33 weeks & tachycardia in baby...?

To sum it up...at my regular midwifery apt today (after all the regular checks-w/everything normal) we listened to the baby's heartrate w/the doppler.
I could tell immediately that it sounded fast...too fast. After a minute or so I jokingly said "guess that cup of coffee's reached the placenta, eh?" My midwife did not laugh. She paused for a few moments & then said "ah...this is actually kinda tachy...I'd really like to see this come down". I said "yeah it sounds kinda high" at which point she turns it to me to see... 188...197...204...195...201 etc. After listening for several minutes (at the same rate) she says "well...I guess she's just responding to me palpating her...I'm guessing it's just the activity getting her heart rate up..." She looks concerned, but not overly. Asks me a few questions about her movement & then says that there is little point in her listening to her (the baby) again as she is still kicking up a storm. We get thru the rest of the apt, I book my next one (2 weeks from now) & go.

Background:
2 days ago (Aug 7) was my due date with the baby that I miscarried 4 weeks before conceiving this one.
Maybe I'm just being paranoid...but the apt hasn't sat well with me & to be honest I'm really concerned.

About 4-5 days ago I was kept awake all night with kicking/movement on my bladder/cervix...I SWORE that night that she had flipped into a breech position. It was really weird. I'm now sure that she is head-down, which was confirmed by my midwife today. Since that night she has had a lot of hiccups & has been moving a LOT, especially at night...she keeps waking me up with her movement. I have had a lot of lower backpain (& hip pain...so I've attributed it to being normal pelvis-separating-pain) & braxton hicks ctx (but this is my 6th baby so I figure it's pretty normal). I have had a lot of headaches this pregnancy...but my blood pressure has been normal (as was my dip-stick thing today) so I'm pretty sure I don't have pre-eclampsia or anything like that.

Minor issues which may or may not factor into any of this...
#1) I am only 139 lbs...I was 135 when I conceived...125 at my first midwifery apt. (lost a bunch due to morning sickness) which makes my on-paper weight gain to be only 14 lbs.
#2) My hemaglobin (sp?) came back at 115...which as I understand is borderline normal/low.
#3) I have had a preemie (36 week) baby 6 years ago & all 4 of my girls births have started with PROM between 36 & 38 weeks which have lead to hosp. inductions w/antibiotics.
#4) I am a coffee drinker (I was only able to kick the habit for the first several months) I drink 2-3 cups per day. I have done this in every pregnancy except for #2...without problems. (I don't think that the ONE cup of coffee that I had an hour before my visit this morning could have caused her high heart rate...at almost every visit I've just had coffee & it's never caused a high heart rate before)
#5) I don't really eat meat...chicken, fish, shellfish, eggs, dairy...yes...but not red meat.
#6) I don't smoke, take drugs, drink booze, have any pre-existing health problems.

Here's my biggest fear...
that the other night she did flip into a breech position & when she flipped back has entangled herself in her cord & is now demonstrating different behaviour (activity & heartrate) for her. And by ignoring her high heart rate today I may cause her to die in utero.
Sorry if that sounds really paranoid...but I've worried the whole pregnancy (well...tried to remain positive) that something will happen to her & we'll lose this baby, too.

Please give me any thoughts on this...
Would it be reasonable to ask my midwife to listen to her heart again in the office later today?
Or does this warrant a NST in the hospital?
Or an ultrasound to check for cord/position/etc.?
Or should I relax & forget about it? Am I over-reacting?