FIRST BIT OF ADVICE- IF YOU DON'T GET YOUR DEGREE, DO NOT GO TO A FOR-PROFIT SCAM "SCHOOL". Most only want your government money anyway...
Can some classmates help you bring up the D?
What possibilities does the professor offer? Maybe he will say something close to this: (if you make a 90% score on the final, or A on the term paper, in addition to nothing lower than a single C on pop tests [one a week??] you likely will have a solid C). What weight does the final exam carry against the low D?
And then- "no degree" is not the end of the world. You can get technical training in many things (computers, stylist, etc.), but pay may not be as good as a degree would get. DON'T DESPAIR. If you were to quit school NOW for a lack of money, one D and the rest good grades, could you pay (in a year or two) the $5000 for a final semester to complete your degree? (I think it is only $5000 for a state university.)
You can find good office jobs in large universities which pay "ok" but can offer insurance and after 5 years RETIREMENT. (Texas does, anyway). No degree is needed. Can a professor or women's dean help in this regard? I knew a counselor that would do anything for me that he could; just because he saw that I was dead serious.