Pelvic cramping pls help

[Frankieearth]

Hi, I’m a 21 year old female. Occasionally and almost exactly a month ago, I notice(d) that whenever I suck my stomach in I get extreme 6/10 pain in my lower abdomen/pelvic area. I am not pregnant, I am 95% sure I am clean for STIs, I am in otherwise good health. But this cramping happens occasionally/monthly (usually after my period in the first week of my cycle) whenever I suck my stomach in or apply pressure to the area. I am on deostrogel mini pill and flucanozole for persistent thrush. The pain is usually persistent (almost like trapped wind) but then is sometimes followed by cystitis symptoms like frequent urination and pain in my urinary tract. Has anyone experienced anything similar? Thanks :)