You've been here 5 months already - on what visa?

I'm sorry to say, but if you can't support yourself, and your boyfriend can't support you, I can't see you getting a visa approved... even a WHV you need to show you won't resort to public funds.

There are loads of other ways to enter the country for longer periods than 6 months.

Are you eligible for a WHV?

Do you have any UK or EU ancestry? If your parents or grandparents were UK citizens you might be eligible for Right Of Abode. Likewise, if your family roots are Italian or Dutch or French, you might be eligible to apply for a European passport, which would allow you to live and work anywhere in the EU, this includes the UK.

Are you eligible for the HSMP?

Have you looked into Work Permit employment? If, for example, you're a nurse or teacher or doctor or engineer or some of the other occupations listed on the Shortage Occupation list (you can find this on the Work Permits UK website) then you stand a pretty good chance of getting an employer to sponsor you for a Work Permit.

How about going back to school? Study at a recognised college or university for a minimum 15 hours per week and you can get a student visa. This will allow you to work up to a maximum of 20 hours per week.

Loads of options there, do any of them apply? Note that if you're here on a visitors visa then you can't apply for any of them from the UK, you will need to go home and apply from there.

I would *never* suggest anyone marries for a visa. More importantly, if you're here on a visitor's visa you're not allowed to get married in the UK and you're not allowed to switch to a Spouse visa.