Ireegular period. Yet help me please!

My bf had fingered me on 24th of last month and he might or might not have precum on his hands and the time when he got his precum would have been 10 mins prior to fingering and after which we fooled around for 10 mins and then he inserted his finger in my vagina he did not ejaculate and I've had irregular periods but now my periods have been delayed for like 15 days and my last period was delayed by 14 days I took a pregnancy test on 11th which came back negative. My period was supposed to come on 4th of this month, I also had little light brown spotting on 14th of this month. I also had was losing chunks of hair just a month ago and I had sudden weight gain 2 years ago. I don't feel weak, nauseous, constipated, no frequent urination, no vomiting and no exhaustion. I have had lower back pain on and off. I don't know what to do can I be pregnant. He says he did not have precum on his hands but he could have had, and I still have not got my periods yet help me please!