How early can you catch on that you're pregnant? What are are signs and symptoms to look out for? Whats the earliest sign to notice?

Breasts were really sensitive, was getting cramps that were similar to period cramps, always felt warmer and always exhausted even if my job isn't very physical, my poor husband had to deal with my insane mood swings too lol I wasn't expecting to be pregnant and thought my period was off the chart again because i used to have PCOS but turns out i was actually pregnant.