Has this happened to anyone else or am I crazy?

Tomorrow I will be 4dpo and I just feel... Off I guess you can say. I woke up with cramps this morning... And I NEVER cramp.... Like ever. I've been feeling nauseous on and off all day and I've been craving chocolate... Which is odd because I rly don't like chocolate... Or any sweets to that matter. My boobs are also very sore and tender... And I've been having dizzy spells all day... Me and my SO have been TTC... Am I crazy or could this rly be happening? I've read some stories on line that some women have symptoms as soon as they conceived and I'm just wondering... Any input?