Ruining my relationship

Hi I have been going out with my girlfriend for about 10 months now and everything was going fine for the first few months but lately it has went downhill because of my paranoia and insecurities. I seen to be checking up on her on a regular basis and have to know whats shes doing all the time when shes not with me or talking to me I always think she is talking to other guys or doing stuff behind my back. We seem to be fighting all the time over me blaming her for doing things which she doesnt do. We got very close really quickly and I love her to bits and really dont want to lose her because she is such a nice girl and has put up with alot of my insecurities while another girl would have probably left me ages ago. Ive noticed lately she is not as close to me and im guessing it is because i keep getting at her. All I want is to have things back to the way they were before cause now I spend most of my time over thinking everything and do spend a good bit of my time crying cause im always worried about her doing something behind my back. She is also starting her final year of university and worried that she will find someone else when shes there either in her class or a night out. I does seem like I dont trust but she has give me no reason not to trust her i really need help cause I know if this relationship ends because of my insecurities I know I will regret it for the rest of my life because I dont believe I will find another girl as nice as her and I will put up with all the stuff I have put her through. Would appreciate any advice

You need to get some help/counselling with respect to your own insecurities. You need to feel confident enough in yourself to know that you a worth being loved and respected by your girlfriend. She obviously does love and respect you as you would not have been together this long otherwise. It is a good first step that you see your own weaknesses and the affect they are having on your relationship. Tell your girlfriend that you are sorry for your behaviour and that you know you have insecure feelings that are not caused by anything she has done and that you are taking ownership of those feelings and seeking help to deal with them. If she is truly the one for you she will respect you for being honest and for telling her that you do trust her and that it is your feelings that are the issue. You need to start thinking the best of her rather than letter your securities cause you to be thinking the worst. You will get out of your relationship what you put into it, if you give trust, show love and are open and honest and she is the right one for you you will get it back.

Thanks KAZBO12 for the response was really helpful thank you. i have actually booked myself in for counselling so im hoping this helps and will improve my relationship.