Oven Issues

[SIZE=3]During a self-cleaning, received a F3 code. Turned it off, unplugged to reset. Months later, did it again, and oven really smelled. Oven smells during regular baking. Made me feel sick. Stopped using oven.[/SIZE]
[SIZE=3]Using 350° as an example, the pre-heated light will beep, with temperature about 150-200°. Used to beep when at 350°. Takes forever for oven to heat to desired temperature. Cannot increase/decrease oven temperature for second baking. Have tried adjusting temperature by manufacture recommendations, but still doesn’t heat correctly. [/SIZE]
[SIZE=3]What parts should I buy or is it worth repairing? Thanks[/SIZE]