Coughing for about a month,diagnosis ideas?

I've been coughing for what seems to be around 2 week cycles. I started coughing and perhaps even had a small fever when I first got it during the first 2 week cycle. If it was a fever, it was nothing big and was only one night. I coughed for about 2 weeks, coughing got worse for up until about a week, then it started to die down after the next week, and it seemed like it went away.

But then the cough came back, progressing the same way minus the possible fever, I did have diarhea after the first 'cycle' and just had diarhea again, while my cough is seemingly 'dying down'.

I'm really tight on money and visiting a doctor would put me back a bit, looking for any ideas/advice. I suppose if it seems like that bad of an issue I'll just go to the doc.