At what point should I be concerned?

Laura
It's been 13 weeks since my last real period. 
5 weeks ago I took a pregnancy test and it was negative, which is not a surprise because my periods have always been irregular (for the last 16 years and I'm 27). 
When my period has been away for a long time like this I usually expect to have a really heavy flow when it comes back with all the PMS symptoms ten fold. 
• 4 weeks ago I got those PMS symptoms but no flow was seen. 
• 3 weeks ago started the brown discharge that isn't uncommon with my irregularity. 
But it hasn't stopped, most days its a brown, sticky dry mucus, and some days it will be a slippery mucus mixed with blood. 
I honestly don't know what to do... Would a douche help clean out whatever is going on? I don't know because I have never done it. And at what point should I be concerned and fork out my limited income to see a doctor (I don't have health insurance <insert sad face here>)?