Welcome and thanks for the query
Blood spots after wiping with toilet paper can be due to spotting from vagina , can be uterine , cervical or due to vaginal laceration.Urethral injury
can also give rise to spotting.Most common cause is an irregular cycle with scanty flow.As you haven't had your periods since XXXXXXX so please get it investigated like blood tests for thyroid
profile , FSH , LH levels and an ultrasound
scan.You may be having PCOD
as you mentioned you are overweight
with delayed cycles.It is better to get examined by your gynaecologist.
Any further query is most welcome