Does anyone else get this?

Every so often (few times a year maybe?) my nipples will get sensitive, sometimes to the point where if my bra moves it hurts. However, these past few days I've got sensitive nipples again, but like nothing I've had before! I don't have the largest ones, but my boobs are hardly small, and every time I lean over a table etc my nipples feel it (they seem to be half erect too?!). The more I have to reach things on the table, I'm a mature university student revising, the more I can feel my nipples!  Please tell me I'm not the only one that gets this? It feels like they're cold for no reason. 🙈 thank you!