Try not to worry about it, it might actually be good to let it out! I'm not in therapy, but have talked to a couple of different professionals recently about issues I'd been having....and I did the exact same as you! I would go in there to talk to them feeling okay...and as soon as I started talking I starting bawling...and it lasted the whole time I was there! I think its normal when your opening up to be very emotional.

You mentioned you hadn't really opened up this way before, so I think in time you will be able to talk more and cry less. Hang in there