First, it isn't the style of saddle that makes your comfortable, it is how well made it is. I don't get rid of a lot of saddles--I have 2 Western, 4 English and about 8 McClellans, and no, I won't give a sales pitch for them.
My most comfortable saddles are either my one cheap English that is 20 years broken in--you don't have time for this!--or the comfortable McClellan's that DH and I didn't sell to somebody else.
First, keep the Western for the time being bc when you find what you like you can sell the whole rig as a matching set.
Second, you need to try the BEST name-brand Western saddles, and, if I was in market for a Western saddle, I'd be looking for a flexible tree, IMHO.
You will be in pain riding a saddle that is too small and though you can handle one a bit too large, I would suggest a perfect fit. I ride a 17 1/2" English, and I ride a 15" Western. You probably fit that range.
Have you gone to any actual tack shops? We buy SO MUCH online today, it's hard to remember that you will be able to sit on them there to really get a good feel. Remember, well made western saddles are designed for ALL DAY riding. Yours obviously doesn't fit you well, or you'd be bragging about the rides you took in it.
I agree that a good English saddle is great to trail ride in, but the rings aren't as durable to tie stuff on as a Western is. DH and I usually tie the following to our saddles while trail riding all day:
--leather saddle bags
one for extra reins, girth, punch, etc. and snake load/regular load pistol
one for first aid (people on one side, horses on the other)
--canvas saddles bags (lunch, etc.)
--gum blanket (rubber CW raincoat)
--metal picket pin (obvious)--with grazing rope
--feed bag, with grain for lunch break and one complete extra bridle
--2 extra canteens, with hand-made leather swing that snaps to rings on saddles
Here is my good mare on the last trail ride trip in SD 3 years ago.
Have you considered a Steele saddle? Steele Trail Saddles by Custom Tree and Saddle
The people I have run across (while trail ride camping) swear by them, and they are very much like an Aussie/Western cross. They make models withOUT the horn, but with many places to tie to. I am considering buying one very soon.