15 wks is too early to feel preg, earliest flutter starts ard 16weeks-21 wk. sides of lower ab could be ur round ligament stretching as bb grows. as long as no bleeding, shld be safe. see doc if you have to but dont worry too much. I have this pain on n off, confirmed by gynae its round ligament (she even says this pain will only get worse lol) and bb seem to have grew bigger aft the ligament stretch.