Why am I having pregnancy symptoms!?

This is so frustrating! I had unprotected in December (3 months ago) and haven't had my period since but have continuously had tender that get really swollen at night, abd. pain, nausea and decreased appetite during the day...I keep thinking, okay this is PMS, I'll have my period soon!...Nothing...it's been 4 weeks since I saw a NP who also did a blood test...:( I have another appointment but I'm afraid they will send me home without answers to my current state like the last time...Any help would be greatly appreciated!!