Need advice!

I usually have a pretty normal cycle .. My period last for 4 days with a day of off and on spotting at the end. Over the holidays, my SO came home from the military for a little bit and we were trying for a baby. Before my January period, i took a test and it came back negative however, my period came and was only 2 days and one of those days was just spotting. I thought it was weird and took another test, but again negative. I waited for this month and the same thing happened. My period started with a day of spotting and was light the next day. I get no normal symptoms of my period either .. No normal PMS or crazy mood swings. No normal cramps or anything. What could have caused this? Is this my new normal or should i go see a doctor? Any advice helps.