hi,welcome to HCM
i understand what you might be going through...
ok,lets discuss and solve one at a time...
1..thyroid problem which might be causing bleeding p/v,,irregular periods
,wt.gain,disturbance in apetite and digestion..
so get a thyroid profile diagnose whether hypo or hyperthyroid and get treated accordingly
and follow physicians advice
2..brown discharge and bleeding after sex can be due to vaginal infections(bacterial,fungal,chlamydial..or cervical polyps,dysplasia
consult a gynaecologist to examine you ,get endometrial.cervical punch biopsy,vaginal discharge
...and proceed accordingly
i suggest you to donot worry,eat properly healthy nutrtion,maintain general condition fit,follow drs advice
bye take care..