Cant get over the past, please help

Its currently 6:24, i cant sleep. my girlfriends made some really bad decisions in the past. well not really bad but im just very jealous so i consider them bad. and i just cant get over them. the thought of her past relationships and encounters creep up on me during lots of times of the day and make my whole mood go lower than ever. i seriously cant stop thinking and probably the only way i stop thinking is talking to my girlfriend about it but usually she doesnt give me the responses i want or she just says she doesnt want to talk about it. not only that but right now shes on a one week cruise and theres no service where shes at so i cant talk to anyone. also this just happend, since she has no service she told me to login her snapchat and keep up her end of our snapchat streak for her while shes gone. well i snooped through her messages, yes i know im the worst. but i felt like shes been hiding more of her past and wouldnt tell me. turns out she was, i found lots of things i wish id never seen. now the past is just messing with me and i have nobody to talk to about it with. my family would just tell me its just a teenage relationship it happens blah blah blah but whatever if it is or if it isnt, i have feelings and oh man does this hurt. i love her dont get me wrong, but its so consistant that i learn new things about her past, every month or couple of weeks i learn something new. it just stacks up in my head and i keep thinking about every single one of them till my heads blank. these thoughts make my stomach turn and literally (maybe this is an actual thing) make my heart hurt. its so overwhelming i dont know what to do or think. i also dont want to tell my mom about it because shes got a handful of things on her mind already and asking her for a therapist would just stress her out even more. my dad and i almost never talk. is there an online therapist i can talk to? or can one of you guys help me on messages or snapchat? something, anything really. now the suns up and thinking too much led me to no sleep.