If I am feeling out of breath, could I have preeclampsia?

Not typical. Classic signs & symptoms of preeclampsia include swelling, especially in hands and face, protein in urine, elevated BP and possibly (w advancing, more severe forms) severe headaches, visual disturbance and right upper quadrant pain. See your doc immediately. Sob is most commonly related to normal changes in respiratory/cardiac function and weight changes-check w your doc for persistent sob, though.
Get seen tody. If you are well into your pregnancy & feel bad it is worthwhile to call your OB and or just go to labor & delivery & have them check you over. The rise in blood pressure in pre-eclampsia & kidney changes can come on quickly & have troubling consequences.