x2 on the tapeworm.
The thing is kid many of us here actually know what it is to eat that. Take myself, now standing at 210lb and 5'8 i find it a hella chore to eat that, and only touch that amount when bulking. Not only this, but i have (or had maybe) a very fast metabolism and don't gain any tissue easily.
A good estimate for one's BMR is the simple sum of LBM(weight-Fat%) x 10 = BMR. This is easily in the ball park i have found and is ample for determining a general picture of someone on a forum. Of course you need to know the Active Metabolic rate really.. so lets assume you are EXTREMELY active and call that: BMR x 2.0 (which is so high, it is simply never achieved by a regular trainee).
As you are 140lbs and i would assume say.. 10%, then your LBM is just 126lbs(!). So your BMR is 1260kcals a day and your AMR at the highest of the top level is... 2520kcal/day. Lets EVEN round that up to 3000kcal a day (which having been 140lbs i am confident you could gain on)
I train people and have lots of experience with caloric intake and expenditure, and how this relates to bodyweight etc.
Now, aside from it being difficult to eat 5000kcals in the first place, someone with your LBM who was to actually eat 5000kcal for the necessary length of time WILL gain weight. The truth is, many people believe they are eating 5000kcal (or whatever) but do not count, do not keep it up or both. If you estimated it, you were wrong. If you just did 1 week - it wasn't long enough. If you TRULY ate that much for 2, 3 or more months then you either A) need to get the worms taken care of, B) need to get the hyperthyroidism issue taken care of or C) need to stop running 5-10 miles a day alongside your 4-5x/wk weights and manual labour job..
This is what i think - if you aren't a BS'er - and if you are, maybe a lurker will benefit from the 5 mins i spent on that