Just need to write really...

So been with my partner 3 years and we've decided to ttc. We've been ttc for maybe 2/3 months now officially. Ie with prenatals and such rather than just "winging it" and still nothing... I know it's not long and there's couples that ttc for like over a year but it's getting hard to look at the bfn each month and having the periods and trying again while seeing people get pregnant without meaning to... we've been having sex every night for the last week or so and my partner couldn't finish tonight and even that made me frustrated and upset and I cried. I felt like he done it because he couldn't be bothered but I know he's just tired from working and sex and everything else. I know he wants this baby like I do but my mind seems to be against me... I worry that all the stress on ttc is also what hinders my ability to conceive... I just don't know what to do... how do I keep positive? How do I not get so stressed? What am I doing wrong? How do I make sure this is what he wants and it's not just him saying this to me to keep me happy? How do I stop my depression from ruining things..? I have a lot of questions and very little support in my life. We are doing this completely alone with no support from family and not telling friends atm ad they are all around 19 20 ish and aren't at the appropriate maturity or experience to have a conversation surrounding ttc and babies without making a comment such as "why have a baby? They're expensive and so much effort when you can just wait and go out drinking and fucking about" as if I don't know what a child entails and as if I don't know I have the ability to go drinking and such it's just that I don't want to do that anymore I want to settle down now and just continue with my dreams of having a family with the man I love and finding more mature people to have as friends who have a more similar take on life as I.