No periods, weight gain, increase in breast size, stabbing pelvic pain, negative pregnancy test. On nexplanon, adios max n. Pregnancy chances?

hi i am on nexplanon since January i am 24 and have been on the injection before for 3 years. i stil dont get a period. I recently started taking adios max n was then told that i can get pregnant from taking herbal stuff I have done a pregnancy test and it came back negative but i put on weight and my breast have got bigger and are very tender at times and i have stabbing pains in my pelvic area the past 3 weeks. i was being treated for pelvic inflamation disease but started getting severe pains in my chest so i have stopped tking them. is there any way i can tell if i am actually pregnant??