period 2 days late

My period is currently 2 days late. My boyfriend and I fooled around a bit on December 29th, (which was right around when I was ovulating or a bit after) but we were both fully clothed and it was just grinding. He said his boxers and pants got damp but nothing seeped through, his pants were just damp. I’m currently in day 32 of my cycle and my period tracker is pretty accurate. I’m also experiencing dull lower back pain and very mild cramping. I’ve taken 2tests over the past 2 days and both of them came out negative fairly quickly. He and I haven’t have penetrative intercourse with each other yet either. I know I sound insane, but is there any chance I could be pregnant? Should I wait a bit longer to take any more tests?