I sounds like your parents are not well-informed.
- internships always involve low level work of some sort (including, for some, getting coffee!)
- the math class you took this summer at cc was unrealistic combined with the internship, travel, and need for sleep: whose idea was it? Just be grateful it won't affect your Purdue GPA (so in that sense, good move to do it at CC) but next time, drop it before it gets bad. -GPA of 3.5 in CS at Purdue is something to be proud of
Are there financial pressures behind your parents’ conversation? If so, the CC class could just be the excuse your Dad has been waiting for, but it is a flimsy excuse indeed.
If I were you, I would get support from a counselor and perhaps your parents could come to a meeting and be invited to be open about any concerns they have about you- and the above points could be covered somehow. I think these conversations can be safer with a neutral professional involved and the power balance will be better between your parents and you with the therapist there.