Heartbroken <\3

This is my story i got pregnant with my 1st baby at the age of 17 around feb or mar. But i wasnt so sure since my period has always been irregular. I went to my first checkup on may 28 and the babys heartbeat was low so they set me up for an ultrasound the next day but sadly that same morning at around 2:00 am i woke up cramping and wanting to go to the bathroom really bad i went and i was bleeding nonstop i got scared and knocked on my parents door to let them know so they rushed me to the hospital where they confirmed that i had miscarried that day was horrible xc now its been 2 years and sinve then i have been trying to conceive. Even thoigh i think i had conceived last month because i was logging in my data and all that stuff. I kept track of my fertile window and last week i was spotting pinkish/brown for about 3 days. I guess i had finally conceived but yesterday i woke up with bad cramping and bleeding dont know if it could of been a miscarriage but im sad and gloomy now cause we tried so hard and to think it could have been makes me depressed and think about giving up. My period wasnt supposed to come yet until next month. I get it every 3 months. What do you guys think? Could it have been a pregnancy? How far along could i have been cause i spotted during my fertile wimdow. What can i do so that it doesnt happen again? :( i dont know what to do anymore im thinking about giving up its too sad to think about.