Anxious

Im 14 weeks today and had my 12 week scan what seems like forever away ive seen the heartbeat and also this morning heard it the sonographet said the baby was looking good and was measuring the right size but I just haven't had hardly any symptoms my boons have been sore and have grown and I have been tiered but I just can't get my head round the fact that I'm growing a baby in me and I feel ok I just keep thinking to myself something will go wrong is it just me been paranoid how can I be more positive