Hey @Caz1 - well done on getting thru your active treatment AND the flying fox!!
That 'flat' feeling is totally 'ok' and common. For the 6-12 months previous, we've been regimented by appointments and treatments & scans & stuff ..... on a bit of a treadmill .... and now, someone turned the treadmill off & you feel a bit lost!
Many of us feel that 'flat' & well what to do now!? feeling! And NO - you are NOT a fraud for surviving .... hold that head high, go & crack a bottle of something, with a packet of chips & put your feet up ..... I really like @FLClover's comment - you are a THRIVER!! YES!
Take up a new hobby to mark 'the new you' ... (Ukulele is good but I may be biased!! ;) ) Keep busy - idle hands & all that!
Just get back out there & start enjoying life again cos the rollercoaster we were on just wasn't fun at all!!
take care xx