A 48 day cycle if consistent would more likely than not be anovulatory. A normal cycle is a cycle length of between 21 and 35 days.
It is not correct to assume that ovulation occurs 14 days before the start of the next period. It is not an exact science and ovulation can occur earlier, later or not at all in any given cycle. It is also quite possible to have periods without ovulating.
If this cycle length remains the same I would have a blood test done to see what your hormone levels are like. Your LH and FSH levels should be tested around day 3 in the cycle. If periods are irregular as well (and yours would be seen as this) it is better to refrain from temp charting.
My concern is am really worried at the moment, I have just had my results for my hormone blood tests carried out on day 5 and 21 day of my cycle. I have been informed by my doctor that I have not ovulated however my cycle are very irregular last one was 50 days previously my cycles were 34, 40, 47, 46,44,43 I came off the pill last September and me and my husband have trying to concieve for just over a year now, my husband had a sperm test and he is ok.
I am using the clearblue fertility monitor, 2nd month on CD 32 and still low fertiliy bearing in mind my cycle was 50 days I may be late ovulating. Maybe someone out there is in the same position, as it's the only thing I can think about.
Your GP should now refer you. Infact I would insist now on a referral to a gynae at a subfertility unit asap. You should be seen as a couple by them.
You need a diagnosis first and foremost. If your cycles are irregular these are often caused by hormonal imbalances. In this regard PCOS is a common culprit. You should be checked further to see if PCOS (polycystic ovarian syndrome) is the cause of the irregular periods.
A "normal" cycle is a cycle length of between 21 and 35 days so your periods would certainly be seen as irregular. With cycles like yours it is highly likely you are not ovulating regularly, if at all currently.
I would urge you not to use any fertility monitor/ovulation predictor kit in such circumstances - they are next to useless if periods are irregular. Also these kits can give false readings particularly if periods are irregular.
You will need to be persistant in order to get answers. Do not be fobbed off, seek a referral now to a subfertility unit.