Air carrier First Officer reported having to call in sick due to fatigue resulting from long work hours. First Officer stated many consecutive work days with minimum days off and lack of scheduling flexibility are common issues at the company.

Narrative

I had to call in sick for my trip on Date; and throughout this report I want to expand on why I made that call.The reason for my sick call was fatigue; to the point that I didn't feel fit to fly for the above-mentioned trip. I believe long hours of working caught up on me and made me more tired than I normally am after my trip.In the past 365 days; I accumulated 967:XX hrs. of block time and many times I went above 990 in the past few weeks. If it wasn't for a couple of conversion from active flying to deadhead; I believe the 1;000 hrs. limit would have been reached. (In the past 28 days I have deadheaded for 14 hrs:XXmin and blocked for 79:XX [hrs]. If I flew the above scheduled trip; the total block could have been close to about 90 hours)Even though few flying picked up by desire here and there; (crew to crew; and mainly to help out colleagues with immediate family needs) scheduling pressure at our airline has never been as high as it has been recently. Long stretch of working days back-to-back; minimum days off; inefficient days with long seats around the airport; and lack of scheduling flexibility is the common issue among my peers these days.As an example; over the holiday I worked 7 days in a row; (a 3 day and a 4 day) and it was legal only because we had 30 hrs. of layover on my 3-day trip. First day of that trip was scheduled to fly X international legs with a block hour of 8:XX which included almost 3 hrs. of seat at ZZZ [airport]. The whole trip worth around 14 hrs. for 3 day and still don't know why that trip scheduled to be so packed and close to FAR 117 limits.There have been many months in the past year that I didn't intend to fly as many hours as I did; but the way schedules are being assigned; you try to pick up something with the hope that it brings your monthly credit high enough so that you can drop another trip; but most of the time last minute changes in crew availability makes you work all the extra trips you picked up. Even at times when the reserve coverage looked good; there are so guidelines restricting us from making any safety adjustments to our schedule.Hopefully my report cast some light on my sick call due to fatigue; and hopefully our cumulative effort brings positive changes to our work rules; eventually making it a better; safer; and healthier place to work. Appreciate if this report and other similar report result in any kind of improvement in our scheduling system.