I Dont Want To Loose Her

I met a girl while i was working for a local repair shop i never hit on her out of respect and profesional courtesy. I will admit I was attracted to her and always found an excusse to say hi when she droped off parts.. Ive always been a shy kind of guy and have a problem talking to women and as a year went by   weve become good aquaintences. when i noticed i hadent sen her in a week i asked around and found out she got fired. although i was dissapointd i went on with life and wonderd if id ever see her again. a couple months later she popped into the shop to have us look at a noise her car was making we diagnosed and repaired the problem and we sat and talked for a few minutes.  i didnt charge her for the labor because she was always so nice to me. and i liked her.  about 2 months later she called me at the shop and asked if "We could hang out sometime"  things quickly grew and we were happy and in love but i always thought there was something she was hiding... as months went by we had our share of problems like any new couple but we were always able to patch things up. then one day weekend in sep i was at the end of my rope because she wasnt bringing me around family so i bought her dads fav. beer and knocked on his door and introduced myself he quickly turned me away shortly after i recieved a phonecall from her  and she was in tears she gave me some time over the weekend and the folowing week she broke up with me.. we stayed on partial good terms untill i noticed the guy she said was her "ex" always around i began to follow her and look for her i used public information to find her familys address, names, jobs and eventualy leaned that the" ex" was her "other boyfriend" whos been around the whole time and finaly found his house, job, address and the rest of his familys as well about three months went by of this and my friends and parents figured out what i was doing they were able to get me to stop for the most part and she also caught me and told me to stop. but when i was near one of those places i couldnt help but drive by... more recently she came back into my life and came clean about everything and all the lies also admited to haveing a drug problem of her own  and asked for my help and support. i did ok for about the first week and then fell into my old ways once again she caught me and i ceasced  the activity untill last week when she began to become distant again after breaking up with the Boyfriend and i started following her in fear that she might use again after being clean for 5 months this past week i initiated a scilence where i would only say good morning and goodnight but began following her again well lastnight i couldnt find her car and drove by the bar she goes to with her family and saw her outside something in my switched and i started following her and her mom from the bar to her moms house about half way there i realized what i was doing and turned off and started for home in the proscess i got lost(ive never deviated from the main streets they were using) and got stuck on a couple one way streets and ended up turning right behind her mom and right in front of her... i quickly turned off and got myself situated and back on the track home but couldnt fight the urge to drive by her house before i went home when i got home i texted her goodnight like i always do and she quickly askd if i drove by .. i could not lie to her so i told her i did and then tried to make contact with her untill she turned her phone off i left her a note explaing myself. wich i asked her if she got.. she did reply that she got it  but didnt want to talk right now... i feel terible and have tried to find a support group to help me before i do something violent and or get served with a restraining order or worse yet loose her forever if i havent already.. andi dont even know where to start or who to talk to