39% seeing 4th does seem a very high, what sort of hands are you calling or raising with?
Personally i don't like to put any money in the pot unless i have:
*(Probably) the highest pair (usually Js or better). eg.

*A live pair with a live A or K kicker. e.g.

*A live pair with a live straight-flush kicker. e.g.
And you should fold on third if you're fairly sure someone has a higher pair, e.g. if you have Js and someone showing a Q completes and a K raises you should just fold, unless you have an Ace (prefereably suited with on of your Js). If playing these hands you should complete/raise not call, unless lots of ppl have already called in front of you and your raise is unlikely to get them to fold, in this case bet/raise on 4th instead. The lower your pair the more important it is for your cards to be live, Aces and (sometimes) Kings you can play if all the aces or kings are out, you should fold anything else, unless you have a live (pref. suited) ace as your kicker.
*3 to the flush with no more than 2 of your suit out (unless you have the A and another high card, then maybe play with 3 out), e.g.

. If two of your suit are out and your cards are low with little chance of a straight (e.g.

) you should probably fold if raised, as you'll likely be raised on 4th as well, and your draw is very weak. If you have over cards, esp. if you have the highest card showing you should raise rather than call on 3rd.
*3 to a straight with no more than 1 of you adjacent cards out, and no more than 2 of the top and buttom cards out e.g. if you have

and you can see other players holding a Q a K and a 7 you should probably fold. The higher your cards the better, espically if you have over cards to what anyone else is showing.

is rarely worth playing unless you can play it cheaply into multi way pot and all your cards are live. A gap straight is playable, as long as you can do so cheaply and none of your gap cards are out, e.g. you have

and no tens are out, prefereably it should have something else going for it (i.e. high cards or suited cards).
*High cards, 3 live high cards (e.g.

) is playable if atleast two of them are higher than any card anyone else is showing. Idealy all your cards should be live, as well as the remaining cards for a broardway straight. If two of them are suited in a live suit, then this is a bonus. If theres a complete and a raise on 3rd then someone probably has a wired high pair and your cards aren't live, so fold. According to PT AKQ is my biggest lossing hand, its not as good as it looks, as you start off behind, and by the time you've made a pair, someone else probably has two pair, so be careful.
Trips and 3 card straight flushes are pretty much always playable.
Seeing 5th street with most of these hands is okay without improvement, unless someone else shows alot of strenght (e.g. someone pairs their door card, you suspect they have trips) or alot of the cards you need go to other players. If you hand is good enough to see 4th its usually good enough to see 5th as well, if there isn't too much action. If at 5th you havn't improved your drawing hand (i.e. you still only have 3 to the flush or str8) then fold, the chances of getting running needed cards of 6th and 7th are tiny. If you think your high pair is still highest keep betting, if you think your pair has been beaten fold, unless you already have two pair, all your cards for the fullhouse are live, and there is enough money/players in the pot to give you the odds to chase.
You seem to be lossing more than half your show downs as well. I can only guess, but it would seem your either bluffing or chasing too much, or both. Its realatively easy to tell when your behind in stud, and if you think your behind you should fold unless you have a strong (live!) draw, e.g. four to a flush. But more than 10% of hands you are dealt going to show down is too high, unless these hands are being checked around, you're either calling or betting out with too many weak hands or weak draws.
Also its usally best to give ppl credit for the hand they're representing, if someone showing an Ace raises on 3rd and bets on 4th, unless you have a good reason to not believe them (e.g. they raise every time they have an ace, or if you've already accounted for two of the aces (and prefereably they're in your hand), then just fold. Sometimes they might not have the ace, or maybe sometimes they do but don't improve you'll win with two smaller pair, but most of the time the chaser loses. Just pay antention, if someone raises too often (i.e. everytime they have an ace or king) then call them down, or better, let someone else call them down, as theres rarely a shortage of ppl willing. Bluffing is a pretty marginal activity in low limit stud because half the players are complete calling stations. I've lost count of the number times someone has called me down the river with a single small pair and no draw, so i very rarely bluff, theres little need or value. Let the calling stations take money off the bluffers, and you take it off the calling stations.