Even though you are very young, I suggest you make a Drs. appt. or even go to the ER to see if anything is going on. Yes it could be due to your losses and is making you very aware of your own health, but get yourself checked. It could be nerves, asthma or a host of other things. Don't sit and ponder WHAT it might be, get an answer.
Drs. would rather see someone get checked and not have anything serious going on rather then have them come in when there is a serious problem that could have been avoided if checked early.
Take care, and good luck...JJ...