I won't say not to stress about it because no matter what anyone here says, you're going to stress about it. When you're worried about your child of course you're going to stress about it! You should speak to your HV, tell her your concerns, and get a professional perspective.
Are there any social skills based playgroups or classes in your area like Toddle Talk, Jo Jingles, Hartbeeps, etc? Sure Start (if there is one still in your area) sometimes do classes or group based around communication and social skills such as Five To Thrive or Learning Together Through Play. It could be worth looking into.
At 12-18mo DS was walking, could repeat words back to us, loved cuddles, climbing, and his dummy. He was, generally speaking, really happy and a lovely little boy. Looking back now there are a few things that stood out but we didn't think anything of until much later. He didn't play with toys. He liked toys and would give them a cursory once over but then they'd be abandoned and he would spend his time opening/closing doors, emptying/refilling the bookshelf, and turning the washing machine on/off. He hated loud noises, made plenty of them himself, but things like an ambulance going past with the siren going or a handdrier or street sweeper would have him sitting in the pushchair shrieking in terror with his hands on the sides of his head. He hated nappies, he wasn't ready for potty training as he didn't have awareness before he needed a wee/poo but as soon as he had done one in his nappy he would bring me a fresh nappy and lie down on the floor with his legs in the air, waiting, as if to say "get this thing off me!". When he did potty train,shortly after he turned two, he was reliably clean and dry within two days. He liked repetition, the same three nursery rhymes and actions over and over, if I sang them in a different order he would shake his head and cover my mouth until I sang them in the right order.