In a constant state of panic

Hi! I'm 15 weeks tomorrow. My last scan was at 13 weeks for a growth check-up and all looked fine that day. It's just that I really don't feel anything at all (except the odd cramp every now and then and the sharp pain in the boobs). Is one supposed to be able to feel baby at this stage? This is my first and I keep panicking that something bad has happened. How can I reassure myself? And how would I know if something doesn't feel right? My next scan isn't for another month and I'm just overwhelmed at the moment. Thanks for listening!