Dent On Penis/foreskin

Hi, Ive had a few problems that have been ongoing for the past few months and driving me insane. After a prolonged period of masturbation a lot of strange things have been happening.
Firstly I noticed a bump on the right hand side of my penis, it can be just about felt when flaccid and easily felt when erect. This freaked me out big time at the start but not as much now because of other problems. It seems to have got a bit smaller but is still there and feels like it could be connected to the base of the penis on that side because of a dull pain at times. It has been there for 9 weeks.
About 6 weeks ago i noticed when im erect there is "ridge" under the head of my penis that is parallel to the corona. It can move about and is especially prominent just after ejaculating. It feels like something has swollen up, a vein or something?? just under and around the head of the penis. When im soft and fully pull back the foreskin i can see a slightly raised area under the head of the penis but it is only when im erect that this pops out quite a bit. What could this be?
Thirdly and the most worrying is when im erect and foreskin is fully retracted down the shaft my penis seems to "dent in" on the underside just where my foreskin ends on the shaft. It seems to cut in just after where the foreskin ends and cuts the urethra off at this point making my urethra stick out a lot more from the "dent" to the base of my penis. I have searched everywhere for answers and can find nothing, I really feel hopeless and dont know what is causing this. When fully erect my penis is "cutting in" on the underside where the end of the foreskin tissue meets the shaft. I was thinking it might be too tight or something? Although it seems a bit tighter there is no problem retracting it all and can retract near the full length of my flaccid penis. What could this "dent/cutting in be"?? I have searched for answers everywhere and can find nothing. Im thinking about every minute of the day and driving me nuts. Ive been to my local GUM clinic on two occasions and have no STD's. I tried to explain my problem but they didnt seem interested once my tests were negative. They had a look at my penis and said everything was fine when i know it is certainly not. I have booked an appointment with my GP which is in 2 weeks hoping for a bit more understanding.
Im sure what the problems are,
1.) The bump on the side
2.) The ridge under head of penis when erect
3.) The dent on the shaft where the foreskin ends on my
erect penis.

I have read a lot of things what it might be- lymphangitis, thrombosis, thrush, peyronies (although there is no bend).
This has been on my mind since they appeared 9 weeks ago, the dent 6 weeks ago and is seriously worrying me. Any help would be greatly appreciated. Thanks