Irregular Periods. Negative Pregnancy Test. Fluttering In Lower Abdomen. What Do You Think?

i have been having irregular periods for the last few months; a few months ago it came on time but only light for one day. the next month is was ten days late, and kind of light. the next three days late and normal. this month it was on time, and only lasted like three days. this is really out of the ordinary for me, and my periods are always on time and 6 days long.. heavy for two days and then light the rest.. i havent thought i was pregnant at all except the one month with the one day period.. i have taken tests just to be safe and they are negative.. but i have been having very frequent fluttering in my lower abdomen , they stop when i put my hand over it! idk if that is just coincidence, but its freaking me out a little.. ive also never had migraines and that is happening more frequently as well, my hips always hurt a lot.. but i just thought nothing of it.. but i wanted to ask what you would think???