That seems like plenty of fuel. (for 50 i'll do like 1 gel). Temps? maybe you need to pre-hydrate a bit more or stop once and fill up

I'd keep going how you are.. going up a few miles at a time should be ok. Or skip one.. do 37 again and see how it goes this time.

what are you riding during the week? I find those rides set up how my weekend rides go. ie if i'm doing a group ride sat. then I like to ride thursday to get the legs going and then have a rest day beforehand.

Oh and my bday is apr 24th too. i'll be 35 this year so i'm a few behind but you'll be fine