Your missed period alongside a negative
pregnancy test can happen from stress,
thyroid changes, or the fungal infection you're currently treating. Since you're 40 and trying to conceive, this is worth checking properly rather than waiting it out.
Next Steps
Book a gynaecologist visit for a hormone panel and pelvic ultrasound, and get the fungal infection treated separately so it isn't overlooked. Please avoid self-medicating to bring your period on in the meantime.