Internet has been down for 12hrs, Downstream flashing green, Upstream and WiFi blank

Hey there. I've been hoping the whole day that my internet might come back, but it hasn't. It worked last night and briefly when I woke up, but stopped working at around 11am EST. I made an account in hopes that I might be able to find a solution on here.

My modem model is the C3700-100NAS. As stated in the subject, the upstream icon is blinking green, and the downstream and wifi icons are unlit. I had a similar issue about a year ago, and I called in a Comcast technician and also replaced my old modem with this one. I'm not much of a tech person so I can't say for sure what he exactly did, but what I do remember him doing is replacing some splitters inside and outside. That seemed to do the trick. More on my modem, though -- manually restarted it 4-5 time by unplugging the power and coax cable and letting it sit before replugging, sometimes for a couple hours on end. Didn't work though. Called Comcast, only for them to suggest that I do the same thing.

Basically, from what I can gather, I don't think it's my inside wiring. I didn't touch my modem until it stopped working so I have doubts it's the hardware. I can only assume it has something to do with outside wiring. I reported it to them and they said they'd have a look. Aside from that, I'm really not interested in having a tech come in to check my wiring and having to pay them another $100 or so. Can anybody help me out?