When 3mm is a Big deal

So, I've been absent from the blog world for a while.  This is partly because my camera is broken and the "thingy' I used to download my memory card onto my computer is missing.  But mostly, it is because my life has been crazy and I have been trying to process it all.
When last I mentioned my IVF cycle, I noted that 15 eggs had been removed.  Of those, four embryos were viable and returned to me.  Next followed 2 weeks of feeling lousy while my body responded to the over stimulation of my ovaries and mega hormones.  I was feeling pretty miserable.  I was convinced that the IVF wouldn't work and truthfully, I was beginning to not care.  I just wanted my non-hormone body back.  Then, the day before our 15th wedding anniversary, my husband came home unable to speak.   I called 911 and he was diagnosed with a TIA or mini stroke.  It can't be proved because thankfully, all his MRIs and CAT scans came back normal with no damage.  They also played around with the idea of it being some sort of migraine event since he had a terrible headache and eye pain.  Needless to say, our anniversary was spent at the hospital and not the highlight of the year.  However, we were thankful that the event was minor in retrospect, requiring Brian to now take a blood thinner for the rest of his life, but leaving him with no long lasting damage.  The next day, I went for my blood test.  I assured the nurse that I was NOT pregnant, she drew the blood and I went home.  Around 2 in the afternoon, she called me to tell me that I was most definitely pregnant.  I argued with her for a bit, thinking it was impossible.  When you have struggled with infertility for 15 years, were told the success rate for IVF over forty is about 10%, and had the kind of stressful few weeks I had had, you just are reluctant to believe.  But she was adamant, so I hung up, called the hospital and told my husband the news.  Somehow our anniversary seemed pretty exciting after all.

Just yesterday, I went for my first ultrasound.  I am just six weeks along and the baby is only 3mm.  However, we were able to see it's little heart beating already.  We couldn't hear it because the doctor said it had probably just started to beat within the last 24 hours and it was still so quiet.  But we saw on the monitor the little line go up and down.  So exciting.  Everything looks good so far.  It is still so early and I know so many things could go wrong.  But I am hopeful, praying like crazy and still trying to believe this is really happening.  So now, if only I could cure these dizzy/faint spells.  Luckily, nausea hasn't been too bad yet, I know that it could still come.  But I keep feeling faint and weak.  I guess this is normal?   Anyone have any suggestions?