Low blood pressure and low blood sugar levels, both of which are prevalent in pregnancy due to hormone changes, can cause all of what you outlined above.
You did the right thing - lying down, having orange juice are the best things you can do to alleviate this. Also try to keep yourself hydrated.
I have always had the problem of low BP all my life, I was also diagnosed with a condition called neurocardiosyncope. Low BP is more common in the second trimester. Make sure you keep your fluids up (it's very important) and perhaps you should eat something salty (I know in pregnancy we have to watch out but if you're really dizzy I highly recommend it). Usually coffee is not a bad idea, but I would recommend against it in pregnancy although perhaps only one cup and not so strong would be fine and relatively harmless. Also if you feel a dizzy spell coming, try to lie down ASAP and elevate your feet.
Hope it helps. Take care.
Just as the above poster said I had this as well, do the protein and remain hydrated!
I had this happen during my 1st trimester and early into the 2nd trimester (then BP rose again and I ended up hypertensive). I was told to make sure I was very well hydrated and to eat protein - peanut butter was recommended. When you feel the signs on low BP make sure you lie down ASAP - even if you are in a store. Standing on your feet will make matters worse.